Hepatitis c virus ns3/4a protease inhibitors

ABSTRACT

The invention provides novel classes of HCV therapeutics that are orally available, safe and effective HCV NS3/4A protease inhibitors and are less susceptible to drug resistance than existing therapeutics. The invention also relates to pharmaceutical composition of these compounds and methods of preparation and use thereof.

PRIORITY CLAIMS AND RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/522,633, filed Jun. 20, 2017, the entire content of which isincorporated herein by reference for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under Grant nos.AI085051 and GM119345 awarded by the National Institutes of Health. TheGovernment has certain rights in the invention.

TECHNICAL FIELDS OF THE INVENTION

The invention generally relates to novel compounds and methods fortreating HCV infection. More particularly, the invention relates tonovel classes of HCV therapeutics that are orally available, safe andeffective HCV NS3/4A protease inhibitors, which are less susceptible todrug resistance than existing therapeutics. The invention also relatesto pharmaceutical composition of these compounds and methods ofpreparation and use thereof.

BACKGROUND OF THE INVENTION

Hepatitis C virus (HCV) infects over 130 million people globally and isthe leading cause of chronic liver disease, cirrhosis, andhepatocellular carcinoma. HCV is known as a “silent killer” as amajority of affected patients remain unaware of their infection, andover time the acute infection progresses to chronic liver disease. Therate of cirrhosis is estimated to increase from 16% to 32% by the year2020 due to the high number of untreated patients. (World HealthOrganization (WHO). Hepatitis C Fact Sheet (2016); Hajarizadeh, et al.Nat. Rev. Gastroenterol. Hepatol. 2013, 10, 553-562; Razavi, et al. J.Viral. Hepat. 2014, 21 Suppl 1, 34-59.)

HCV infection is difficult to treat, as the virus is genetically diversewith six known genotypes (genotype 1-6), each of which is furthersub-divided into numerous subtypes. Genotype 1 (GT1) and genotype 3(GT3) are the most prevalent accounting for 46% and 30% of globalinfections, respectively. Therapeutic regimen and viral response arelargely genotype dependent with most treatments being efficacious onlyagainst GT1. (Gower, et al. J. Hepatol. 2014, 61, S45-S57; Messina, etal. Hepatology 2015, 61, 77-87; WHO Guidelines for the screening, careand treatment of persons with chronic hepatitis C infection. April2016.)

The recent advent of direct-acting antivirals (DAAs) targeting essentialviral proteins NS3/4A, NS5A, and NS5B has remarkably improvedtherapeutic options and treatment outcomes for HCV infected patients.Four new all-oral treatments have been approved by the FDA: Harvoni®(sofosbuvir and ledipasvir), Viekira Pak® (ombitasvir, paritaprevir,ritonavir, and dasabuvir), Zepatier™ (elbasvir and grazoprevir), andmore recently Epclusa® (sofosbuvir and velpatasvir). (Asselah, et al.Liver Int. 2016, 36, 47-57; Afdhal, et al. N. Engl. J. Med. 2014, 370,1889-1898; Ferenci, et al. N. Engl. J Med. 2014, 370, 1983-1992; Lawitz,et al. Lancet 2014, 385, 1075-; Everson, et al. Ann. Intern. Med. 2015,163, 818-826.)

The DAA-based therapies are highly effective against GT1 with sustainedvirological response (SVR) rates greater than 90%. However, most of theFDA approved treatments and those in clinical development are notefficacious against other genotypes, especially GT3. Moreover, exceptfor sofosbuvir, all current DAAs are susceptible to drug resistance.Therefore, more robust DAAs need to be developed with higher barriers todrug resistance and a broad spectrum of activity against different HCVgenotypes. (Asselah, et al. Liver Int. 2016, 36, 47-57; Pawlotsky, etal. Gastroenterology 2016, 151, 70-86.)

The HCV NS3/4A protease is a major therapeutic target for thedevelopment of pan-genotypic HCV inhibitors. The NS3/4A proteaseinhibitors (PIs) telaprevir and boceprevir were the first DAAs approvedfor the treatment of HCV GT1 infection in combination therapy withpegylated-interferon and ribavirin. Three recently approved PIs,simeprevir (TMC-435), paritaprevir (ABT-450) and grazoprevir (MK-5172),(FIG. 1 ) are integral components of various combination therapiescurrently used as the standard of care for HCV infected patients. Twoother NS3/4A PIs, asunaprevir and vaniprevir, have been approved inJapan. In addition, a number of next generation NS3/4A PIs are inclinical development including glecaprevir (ABT-493), MK-6325 andvoxilaprevir (GS-9857) (FIG. 1 ). (Meanwell, et al. J Med. Chem. 2016,59, 7311-7351; McCauley, J. et al. Curr. Opin. Pharmacol. 2016, 30,84-92; Kwong, et al. Nat. Biotech. 2011, 29, 993-1003; Venkatraman, etal. J Med. Chem. 2006, 49, 6074-6086; Zeuzem, et al. N. Engl. J Med.2011, 364, 2417-2428; Poordad, et al. N. Engl. J. Med. 2011, 364,1195-1206; Rosenquist, et al. J. Med. Chem. 2014, 57, 1673-1693;Pilot-Matias, et al. Antimicrob. Agents Chemother. 2015, 59, 988-997;Harper, et al. ACS Med. Chem. Lett. 2012, 3, 332-336; Scola, et al. J.Med. Chem. 2014, 57, 1730-1752; McCauley, et al. J. Med. Chem. 2010, 53,2443-2463; Lawitz, et al. Antimicrob. Agents Chemother. 2015, 60,1546-1555; Rudd, et al. ChemMedChem 2015, 10, 727-735.)

All NS3/4A PIs share a common peptidomimetic scaffold and are eitherlinear or macrocyclic; the macrocycle is located either between P1-P3 orP2-P4 moieties. In addition, these inhibitors contain a largeheterocyclic moiety attached to the P2 proline, which significantlyimproves inhibitor potency against wild-type (WT) NS3/4A protease.(McCauley, J. et al. Curr. Opin. Pharmacol. 2016, 30, 84-92; Tsantrizos,et al. Angew. Chem. Int. Ed. Engl. 2003, 42, 1356-1360; LaPlante, et al.J. Med. Chem. 2013, 57, 1777-1789.)

All NS3/4A PIs are, however, susceptible to drug resistance, especiallydue to single site mutations at protease residues Arg155, Ala156 andAsp168. Notably, D168A/V mutations are present in nearly all patientswho fail treatment with PIs. Moreover, natural polymorphisms at thisposition are responsible for significantly reduced inhibitor potencyagainst GT3. (Pawlotsky, et al. Gastroenterology 2016, 151, 70-86;Lontok, et al. Hepatology 2015, 62, 1623-1632; Kieffer, et al. Curr.Opin. Virol. 2014, 8, 16-21; Chan, et al. In vitro efficacy andresistance profiling of protease inhibitors against a novel HCV genotype3a replicon. In International Workshop on HIV & Hepatitis Virus DrugResistance and Curative Strategies, Toronto, ON, Canada, 2013.)

Development of HCV NS3/4A protease inhibitors with pan-genotypicactivity and low susceptibility to drug resistance remains challengingbut necessary for improving the long-term effectiveness of this drugclass. An urgent need exists for improved HCV therapeutics, especiallysafe and effective HCV NS3/4A protease inhibitors that are also lesssusceptible to drug resistance than existing therapeutics.

SUMMARY OF THE INVENTION

The invention provides novel, orally available, selective and potent HCVtherapeutics that are safe and effective HCV NS3/4A protease inhibitorsand are less susceptible to drug resistance than currently availabledrugs. The invention also provides pharmaceutical compositions of thesecompounds and methods of their preparation and use.

Compounds disclosed herein include a series of novel P1-P3 macrocyclicinhibitors that were specifically designed to improve their resistanceprofiles. In particular, structure-based studies on the compound-targetinteractions led to compound designs that exploit interfaces with theinvariant catalytic triad and avoid contacts with the protease residuesin the S2 subsite to improve the resistance profile of NS3/4A proteaseinhibitors.

Specifically, these macrocyclic inhibitors incorporate flexiblequinoxalines at the P2 position. Investigation of structure-activityrelationships showed that the P2 quinoxalines with small hydrophobicsubstituents at the 3-position were better for maintaining potencyagainst drug resistant variants, likely due to reduced interactions withresidues in the S2 subsite. In contrast, inhibitors with larger groupsat this position were highly susceptible to mutations at Arg155, Ala156and Asp168.

This new class of macrocyclic inhibitors exhibited exceptional potencyprofiles with EC₅₀ values less than 5 nM against major drug resistantHCV variants. These results further confirm that inhibitors designed tointeract with evolutionarily constrained regions of the protease, whileavoiding interactions with residues not essential for substraterecognition, are less likely to lead to drug resistance.

Also disclosed herein are HCV NS3/4A PIs that extend in the P4 directionleveraging unexploited areas in the substrate envelope to improveresistance profiles, particularly against multi-drug resistant mutationsat Asp 168. As disclosed herein, optimally filling the P4 pocket of thesubstrate envelope improves inhibitor potency while avoiding resistance.Use of unexploited space in the pocket was critical for this improvementby enhanced hydrophobic packing, or fluorine-hydrogen bonding andavoiding forming an energetically frustrated pocket. These strategiesachieved better resistance profiles and higher affinity over bothFDA-approved NS3/4A PI grazoprevir and the parent compound.

Additional compounds disclosed herein include a series of novel linearHCV NS3/4A PIs. These compounds were designed by eliminating the P2-P4macrocyclic linker in grazoprevir, which, in addition to conferringconformational flexibility, allowed structure-activity relationship(SAR) exploration of diverse quinoxalines at the P2 position.

In one aspect, the invention generally relates to a compound having thestructural formula (I),

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring, or a pharmaceutically acceptableform thereof.

In another aspect, the invention generally relates to a compound havingthe structural formula (II),

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof.

In yet another aspect, the invention generally relates to a compoundhaving the structural formula (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound having the structuralformula of (I):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof, effective to treat orreduce HCV infection or a related disease or disorder, in a mammal,including a human, and a pharmaceutically acceptable excipient, carrier,or diluent.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound having the structuralformula of (II):

wherein

each of X and Y is independently selected from O, NH and CH₂, providedthat at least one of X and Y is NH;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group, wherein each R is independently aH or an alkyl group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;and

each R¹¹ is independently selected from H, halogen, or an alkyl group,or a pharmaceutically acceptable form thereof, effective to treat orreduce HCV infection or a related disease or disorder, in a mammal,including a human, and a pharmaceutically acceptable excipient, carrier,or diluent.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound having the structuralformula of (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof, effective to treat orreduce HCV infection or a related disease or disorder, in a mammal,including a human, and a pharmaceutically acceptable excipient, carrier,or diluent.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound disclosed herein.

In yet another aspect, the invention generally relates to a unit dosage.The unit dosage form is comprised of a pharmaceutical herein disclosed.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder.The method includes: administering to a subject in need thereof apharmaceutical composition comprising a compound having the structuralformula of (I):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder.The method includes: administering to a subject in need thereof apharmaceutical composition comprising a compound having the structuralformula of (II):

wherein

each of X and Y is independently selected from O, NH and CH₂, providedthat at least one of X and Y is NH;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group, wherein each R is independently aH or an alkyl group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;and

each R¹¹ is independently selected from H, halogen, or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder.The method includes: administering to a subject in need thereof apharmaceutical composition comprising a compound having the structuralformula of (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder,comprising administering to a subject in need thereof a pharmaceuticalcomposition or a unit dosage form disclosed herein.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositioncomprising a compound having the structural formula of (I):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositioncomprising a compound having the structural formula of (II):

wherein

each of X and Y is independently selected from O, NH and CH₂, providedthat at least one of X and Y is NH;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group, wherein each R is independently aH or an alkyl group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;and

each R¹¹ is independently selected from H, halogen, or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositioncomprising a compound having the structural formula of (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositiondisclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 . Chemical structures of HCV NS3/4A protease inhibitors.Simeprevir, paritaprevir and grazoprevir are approved by the FDA;MK-6325, voxilaprevir and glecaprevir are in clinical development. Thecanonical nomenclature for drug moiety positioning is indicated usingMK-5172.

FIG. 2 . Chemical structures and binding modes of MK-5172 (1) and5172mcP1P3 (2). (a) Compound 2 was designed by replacing the P2-P4macrocycle in 1 with a P1-P3 macrocycle. (b) The binding conformation of1 (PDB ID: 3SUD) and 2 (PDB ID: 5EPN) in the active site of wild-typeNS3/4A protease. Compound 2 maintains the unique binding mode of 1whereby the P2 quinoxaline makes strong interactions with the catalyticresidues avoiding contacts with known drug resistance residues. Thecatalytic triad is highlighted in yellow and drug resistance residuesArg155, Ala156, and Asp168 are shown in blue, red and green,respectively.

FIG. 3 . (a) X-ray crystal structure of WT1a HCV NS3/4A protease incomplex with inhibitor 19b and (b) superposition of WT-2 and WT-19acomplexes. The protease active site is shown as a surface with inhibitor19b shown in orange and 2 shown in blue. The catalytic triad ishighlighted in yellow, and drug resistance residues Arg155, Ala156, andAsp168 are shown as sticks.

FIG. 4 . Comparison of lead compound 2 with analogues (a) 18d and (b)18e modeled in the active site of WT HCV NS3/4A protease. Compound 2 isshown in salmon, and modified inhibitors are in green. The catalytictriad is highlighted in yellow, and drug resistance residues Arg155,Ala156, and Asp168 are in sticks.

FIG. 5 . (a) X-ray crystal structure of WT1a HCV NS3/4A protease incomplex with inhibitor 18f and (b) superposition of WT-2 and WT-18fcomplexes. The protease active site is shown as a surface with inhibitor18f shown in orange and 2 shown in blue. The catalytic triad ishighlighted in yellow, and drug resistance residues Arg155, Ala156, andAsp168 are shown as sticks.

FIG. 6 . Resistance profiles of protease inhibitors in enzyme inhibitionand antiviral assays for PIs with (a) tert-butyl and (b) cyclopentyl P4capping groups. Enzyme inhibitory (blue bars) and antiviral (orangebars) activities against the D168A variant were normalized with respectto the wild-type NS3/4A protease domain or wild-type HCV GT1b replicon.*Indicates value higher than 1000.

FIG. 7 . Chemical structures of designed HCV NS3/4A protease inhibitors.(a) Grazoprevir (MK-5172) is an FDA-approved PI. Change of themacrocycle location (5172-mcP1P3) and optimization of the P2 quinoxalinemoiety led to the parent compound modified in this study. The canonicalnomenclature for drug moiety positioning, and the P4 moiety altered areindicated. (b) The inhibitors designed to extend into the SE are P4-capand P4-P5-cap inhibitors that were based on the parent compound scaffoldwith modifications at the P4 and P4-P5 regions.

FIG. 8 . Resistance profile of HCV NS3/4A protease inhibitors. (a)Enzyme inhibition constants against wildtype (blue) and D168A (orange)protease, and (b) fold change of enzyme inhibitory activity against theD168A variant with respect to wildtype NS3/4A protease. PC and GZR standfor parent compound and grazoprevir, respectively.

FIG. 9 . Fit of NS3/4A protease inhibitors within the substrateenvelope. Inhibitors (a) grazoprevir, (b) parent compound, (c) P4-capand (d) P4-P5-cap inhibitors shown as sticks (orange) in the substrateenvelope (blue). The side chains of the catalytic triad and residuessurrounding the S4 pocket are shown as yellow and green sticks,respectively and the S1-S6 positions of the envelope labeled.

FIG. 10 . Binding modes of P4-P5-cap inhibitors. Surface representationof HCV NS3/4A with (a) superposed substrate peptides (gray; PDB IDs:3M5N, 3M50 and 1CU1) (b) P4-P5-2 (purple) and (c) P4-P5-1 (orange) boundto the active site of wildtype protease. (d) P4-P5-2 bound to D168Aprotease. Substrate hydrogen bonds to Ser159 are shown in panel (a),which the P4-P5-cap inhibitors mimic. Catalytic triad residues arehighlighted in yellow and drug resistance residues Arg155, Ala156,Asp168 and Ser159 are shown as purple, red, green and blue sticks,respectively.

FIG. 11 . Binding of grazoprevir and designed PIs to WT and D168Aprotease active site. Surface representation of (a, b) grazoprevir, (c,d) P4-P5-2 and (e, f) P4-1 bound to wildtype (blue) and D168A (orange)proteases, respectively. The catalytic triad and S4 subsite residues areshown as sticks. Water molecules are shown as non-bonded spheres (red)and hydrogen bonds (gray dashed lines) that stabilize S4 pocket sidechains are displayed. Black dashed line outlines the surface of the S4pocket where the D168A mutation is located.

FIG. 12 . Inhibitor interactions with S4 pocket residues of HCV NS3/4Aprotease. (a) Intermolecular van der Waals (vdW) contact energies forinhibitors with residues forming the S4 pocket in WT protease crystalstructures. (b) Change in vdW contacts (ΔvdW) relative to parentcompound (PC). GZR stands for grazoprevir. Negative values indicateenhanced contacts compared to the parent compound.

FIG. 13 . Stereo view of P4-cap inhibitors filling the S4 pocket of thesubstrate envelope. (a) P4-3 bound to the wildtype protease active sitein surface representation and (b) shown in the substrate envelope(blue). (c, d) same as above for P4-2. Inhibitors, S4 subsite residues,and catalytic triad residues are shown as sticks. In (b) and (d)catalytic triad residues are in yellow and S4 subsite residues are teal.

FIG. 14 . Co-crystal structures of WT1a HCV NS3/4A protease in complexwith linear inhibitors (a) 12b, (b) 12c, and (c) 12d. The proteaseactive site is presented as a light grey surface with bound inhibitorsdepicted as orange sticks. The catalytic triad is highlighted in yellow,and drug resistance residues Arg155, Ala156, and Asp168 are shown assticks.

FIG. 15 . Superposition of WT-1 and (a) WT-12b, (b) WT-12c, and (c)WT-12d complexes, focusing on the differences at the P2 quinoxaline. Theprotease is in ribbon representation (light grey), with bound inhibitors1 (blue) and 12b-d (orange) depicted as sticks. The side chains ofcatalytic triad and drug resistance residues Arg155, Ala156, and Asp168are shown as ball and sticks.

FIG. 16 . Superposition of WT-1 and WT-3 complexes, focusing on thedifferences at the P2 quinoxaline. The protease is in ribbonrepresentation (light grey), with bound inhibitors 1 (blue) and 3(orange) depicted as sticks. The side chains of catalytic triad and drugresistance residues Arg155, Ala156, and Asp168 are shown as ball andsticks.

FIG. 17 . (a) Superposition of WT-1 and A156T-1 and (b) A156T-1 andWT-12d complexes, focusing on the differences at the P2 quinoxaline. Theprotease is in ribbon representation (light grey) with bound inhibitor 1depicted as sticks in blue (WT) and red (A156T), and inhibitor 12d (WT)in orange. The side chains of catalytic triad and drug resistanceresidues Arg155, Ala156, and Asp168 are shown as ball and sticks.

DEFINITIONS

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. General principles of organicchemistry, as well as specific functional moieties and reactivity, aredescribed in “Organic Chemistry”, Thomas Sorrell, University ScienceBooks, Sausalito: 2006.

Certain compounds of the present invention may exist in particulargeometric or stereoisomeric forms. The present invention contemplatesall such compounds, including cis- and trans-isomers, R- andS-enantiomers, diastereomers, (D)-isomers, (L)-isomers, the racemicmixtures thereof, and other mixtures thereof, as falling within thescope of the invention. Additional asymmetric carbon atoms may bepresent in a substituent such as an alkyl group. All such isomers, aswell as mixtures thereof, are intended to be included in this invention.

Isomeric mixtures containing any of a variety of isomer ratios may beutilized in accordance with the present invention. For example, whereonly two isomers are combined, mixtures containing 50:50, 60:40, 70:30,80:20, 90:10, 95:5, 96:4, 97:3, 98:2, 99:1, or 100:0 isomer ratios arecontemplated by the present invention. Those of ordinary skill in theart will readily appreciate that analogous ratios are contemplated formore complex isomer mixtures.

If, for instance, a particular enantiomer of a compound of the presentinvention is desired, it may be prepared by asymmetric synthesis, or byderivation with a chiral auxiliary, where the resulting diastereomericmixture is separated and the auxiliary group cleaved to provide the puredesired enantiomers. Alternatively, where the molecule contains a basicfunctional group, such as amino, or an acidic functional group, such ascarboxyl, diastereomeric salts are formed with an appropriateoptically-active acid or base, followed by resolution of thediastereomers thus formed by fractional crystallization orchromatographic methods well known in the art, and subsequent recoveryof the pure enantiomers.

Solvates and polymorphs of the compounds of the invention are alsocontemplated herein. Solvates of the compounds of the present inventioninclude, for example, hydrates.

Definitions of specific functional groups and chemical terms aredescribed in more detail below. When a range of values is listed, it isintended to encompass each value and sub-range within the range. Forexample “C₁₋₆ alkyl” is intended to encompass, C₁, C₂, C₃, C₄, C₅, C₆,C₁₋₆, C₁₋₅, C₁₋₄, C₁₋₃, C₁₋₂, C₂₋₆, C₂₋₅, C₂₋₄, C₂₋₃, C₃₋₆, C₃₋₅, C₃₋₄,C₄₋₆, C₄₋₅, and C₅₋₆ alkyl.

As used herein, the term “alkyl” refers to a straight or branchedhydrocarbon chain radical consisting solely of carbon and hydrogenatoms, containing no unsaturation, having from one to ten carbon atoms(e.g., C₁₋₁₀ alkyl). Whenever it appears herein, a numerical range suchas “1 to 10” refers to each integer in the given range; e.g., “1 to 10carbon atoms” means that the alkyl group can consist of 1 carbon atom, 2carbon atoms, 3 carbon atoms, etc., up to and including 10 carbon atoms,although the present definition also covers the occurrence of the term“alkyl” where no numerical range is designated. In some embodiments,“alkyl” can be a C₁₋₆ alkyl group. In some embodiments, alkyl groupshave 1 to 10, 1 to 8, 1 to 6, or 1 to 3 carbon atoms. Representativesaturated straight chain alkyls include, but are not limited to,-methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, and -n-hexyl; whilesaturated branched alkyls include, but are not limited to, -isopropyl,-sec-butyl, -isobutyl, -tert-butyl, -isopentyl, 2-methylbutyl,3-methylbutyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl,2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl,2,3-dimethylbutyl, and the like. The alkyl is attached to the parentmolecule by a single bond. Unless stated otherwise in the specification,an alkyl group is optionally substituted by one or more of substituentswhich independently include: acyl, alkyl, alkenyl, alkynyl, alkoxy,alkylaryl, cycloalkyl, aralkyl, aryl, aryloxy, amino, amido, amidino,imino, azide, carbonate, carbamate, carbonyl, heteroalkyl, heteroaryl,heteroarylalkyl, heterocycloalkyl, hydroxy, cyano, halo, haloalkoxy,haloalkyl, ester, ether, mercapto, thio, alkylthio, arylthio,thiocarbonyl, nitro, oxo, phosphate, phosphonate, phosphinate, silyl,sulfinyl, sulfonyl, sulfonamidyl, sulfoxyl, sulfonate, urea,—Si(R^(a))₃, —OR^(a), —SR^(a), —OC(O)—R^(a), —N(R^(a))₂, —C(O)R^(a),—C(O)OR^(a), —OC(O)N(R^(a))₂, —C(O)N(R^(a))₂, —N(R^(a))C(O)OR^(a),—N(R^(a))C(O)R^(a), —N(R^(a))C(O)N(R^(a))₂, —N(R^(a))C(NR^(a))N(R^(a))₂,—N(R^(a))S(O)_(t)N(R^(a))₂ (where t is 1 or 2), —P(═O)(R^(a))(R^(a)), or—O—P(═O)(OR^(a))₂ where each R^(a) is independently hydrogen, alkyl,haloalkyl, carbocyclyl, carbocyclylalkyl, aryl, aralkyl,heterocycloalkyl, heterocycloalkylalkyl, heteroaryl or heteroarylalkyl,and each of these moieties can be optionally substituted as definedherein. In a non-limiting embodiment, a substituted alkyl can beselected from fluoromethyl, difluoromethyl, trifluoromethyl,2-fluoroethyl, 3-fluoropropyl, hydroxymethyl, 2-hydroxyethyl,3-hydroxypropyl, benzyl, and phenethyl.

As used herein, the term “alkoxy” refers to the group —O-alkyl,including from 1 to 10 carbon atoms (C₁₋₁₀) of a straight, branched,saturated cyclic configuration and combinations thereof, attached to theparent molecular structure through an oxygen. Examples include methoxy,ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, pentoxy, cyclopropyloxy,cyclohexyloxy and the like. “Lower alkoxy” refers to alkoxy groupscontaining one to six carbons. In some embodiments, C₁₋₃ alkoxy is analkoxy group that encompasses both straight and branched chain alkyls offrom 1 to 3 carbon atoms. Unless stated otherwise in the specification,an alkoxy group can be optionally substituted by one or moresubstituents which independently include: acyl, alkyl, alkenyl, alkynyl,alkoxy, alkylaryl, cycloalkyl, aralkyl, aryl, aryloxy, amino, amido,amidino, imino, azide, carbonate, carbamate, carbonyl, heteroalkyl,heteroaryl, heteroarylalkyl, heterocycloalkyl, hydroxy, cyano, halo,haloalkoxy, haloalkyl, ester, ether, mercapto, thio, alkylthio,arylthio, thiocarbonyl, nitro, oxo, phosphate, phosphonate, phosphinate,silyl, sulfinyl, sulfonyl, sulfonamidyl, sulfoxyl, sulfonate, urea,—Si(R^(a))₃, —OR^(a), —SR^(a), —OC(O)—R^(a), —N(R^(a))₂, —C(O)R^(a),—C(O)OR^(a), —OC(O)N(R^(a))₂, —C(O)N(R^(a))₂, —N(R^(a))C(O)OR^(a),—N(R^(a))C(O)R^(a), —N(R^(a))C(O)N(R^(a))₂, —N(R^(a))C(NR^(a))N(R^(a))₂,—N(R^(a))S(O)_(t)N(R^(a))₂ (where t is 1 or 2), —P(═O)(R^(a))(R^(a)), or—O—P(═O)(OR^(a))₂ where each R^(a) is independently hydrogen, alkyl,haloalkyl, carbocyclyl, carbocyclylalkyl, aryl, aralkyl,heterocycloalkyl, heterocycloalkylalkyl, heteroaryl or heteroarylalkyl,and each of these moieties can be optionally substituted as definedherein.

As used herein, the terms “aromatic” or “aryl” refer to a radical with 6to 14 ring atoms (e.g., C₆₋₁₄ aromatic or C₆₋₁₄ aryl) that has at leastone ring having a conjugated pi electron system which is carbocyclic(e.g., phenyl, fluorenyl, and naphthyl). In some embodiments, the arylis a C₆₋₁₀ aryl group. For example, bivalent radicals formed fromsubstituted benzene derivatives and having the free valences at ringatoms are named as substituted phenylene radicals. In other embodiments,bivalent radicals derived from univalent polycyclic hydrocarbon radicalswhose names end in “-yl” by removal of one hydrogen atom from the carbonatom with the free valence are named by adding “-idene” to the name ofthe corresponding univalent radical, e.g., a naphthyl group with twopoints of attachment is termed naphthylidene. Whenever it appearsherein, a numerical range such as “6 to 14 aryl” refers to each integerin the given range; e.g., “6 to 14 ring atoms” means that the aryl groupcan consist of 6 ring atoms, 7 ring atoms, etc., up to and including 14ring atoms. The term includes monocyclic or fused-ring polycyclic (i.e.,rings which share adjacent pairs of ring atoms) groups. Polycyclic arylgroups include bicycles, tricycles, tetracycles, and the like. In amulti-ring group, only one ring is required to be aromatic, so groupssuch as indanyl are encompassed by the aryl definition. Non-limitingexamples of aryl groups include phenyl, phenalenyl, naphthalenyl,tetrahydronaphthyl, phenanthrenyl, anthracenyl, fluorenyl, indolyl,indanyl, and the like. Unless stated otherwise in the specification, anaryl moiety can be optionally substituted by one or more substituentswhich independently include: acyl, alkyl, alkenyl, alkynyl, alkoxy,alkylaryl, cycloalkyl, aralkyl, aryl, aryloxy, amino, amido, amidino,imino, azide, carbonate, carbamate, carbonyl, heteroalkyl, heteroaryl,heteroarylalkyl, heterocycloalkyl, hydroxy, cyano, halo, haloalkoxy,haloalkyl, ester, ether, mercapto, thio, alkylthio, arylthio,thiocarbonyl, nitro, oxo, phosphate, phosphonate, phosphinate, silyl,sulfinyl, sulfonyl, sulfonamidyl, sulfoxyl, sulfonate, urea,—Si(R^(a))₃—OR^(a), —SR^(a), —OC(O)—R^(a), —N(R^(a))₂, —C(O)R_(a),—C(O)OR^(a), —OC(O)N(R^(a))₂, —C(O)N(R^(a))₂, —N(R^(a))C(O)OR^(a),—N(R^(a))C(O)R^(a), —N(R^(a))C(O)N(R^(a))₂, —N(R^(a))C(NR^(a))N(R^(a))₂,—N(R^(a))S(O)_(t)N(R^(a))₂ (where t is 1 or 2), —P(═O)(R^(a))(R^(a)), or—O—P(═O)(OR^(a))₂ where each R^(a) is independently hydrogen, alkyl,haloalkyl, carbocyclyl, carbocyclylalkyl, aryl, aralkyl,heterocycloalkyl, heterocycloalkylalkyl, heteroaryl or heteroarylalkyl,and each of these moieties can be optionally substituted as definedherein.

As used herein, the terms “cycloalkyl” and “carbocyclyl” each refers toa monocyclic or polycyclic radical that contains only carbon andhydrogen, and can be saturated or partially unsaturated. Partiallyunsaturated cycloalkyl groups can be termed “cycloalkenyl” if thecarbocycle contains at least one double bond, or “cycloalkynyl” if thecarbocycle contains at least one triple bond. Cycloalkyl groups includegroups having from 3 to 13 ring atoms (i.e., C₃₋₁₃ cycloalkyl). Wheneverit appears herein, a numerical range such as “3 to 10” refers to eachinteger in the given range; e.g., “3 to 13 carbon atoms” means that thecycloalkyl group can consist of 3 carbon atoms, 4 carbon atoms, 5 carbonatoms, etc., up to and including 13 carbon atoms. The term “cycloalkyl”also includes bridged and spiro-fused cyclic structures containing noheteroatoms. The term also includes monocyclic or fused-ring polycyclic(i.e., rings which share adjacent pairs of ring atoms) groups.Polycyclic aryl groups include bicycles, tricycles, tetracycles, and thelike. In some embodiments, “cycloalkyl” can be a C₃₋₈ cycloalkylradical. In some embodiments, “cycloalkyl” can be a C3-s cycloalkylradical. Illustrative examples of cycloalkyl groups include, but are notlimited to the following moieties: C₃₋₆ carbocyclyl groups include,without limitation, cyclopropyl (C₃), cyclobutyl (C₄), cyclopentyl (C₅),cyclopentenyl (C₅), cyclohexyl (C₆), cyclohexenyl (C₆), cyclohexadienyl(C₆) and the like. Examples of C₃₋₇ carbocyclyl groups include norbornyl(C₇). Examples of C₃₋₈ carbocyclyl groups include the aforementionedC₃₋₇ carbocyclyl groups as well as cycloheptyl (C₇), cycloheptadienyl(C₇), cycloheptatrienyl (C₇), cyclooctyl (C₈), bicyclo[2.2.1]heptanyl,bicyclo[2.2.2]octanyl, and the like. Examples of C₃₋₁₃ carbocyclylgroups include the aforementioned C₃₋₈ carbocyclyl groups as well asoctahydro-1H indenyl, decahydronaphthalenyl, spiro[4.5]decanyl and thelike. Unless stated otherwise in the specification, a cycloalkyl groupcan be optionally substituted by one or more substituents whichindependently include: acyl, alkyl, alkenyl, alkynyl, alkoxy, alkylaryl,cycloalkyl, aralkyl, aryl, aryloxy, amino, amido, amidino, imino, azide,carbonate, carbamate, carbonyl, heteroalkyl, heteroaryl,heteroarylalkyl, heterocycloalkyl, hydroxy, cyano, halo, haloalkoxy,haloalkyl, ester, ether, mercapto, thio, alkylthio, arylthio,thiocarbonyl, nitro, oxo, phosphate, phosphonate, phosphinate, silyl,sulfinyl, sulfonyl, sulfonamidyl, sulfoxyl, sulfonate, urea,—Si(R^(a))₃, —OR^(a), —SR^(a), —OC(O)—R^(a), —N(R^(a))₂, —C(O)R^(a),—C(O)OR^(a), —OC(O)N(R^(a))₂, —C(O)N(R^(a))₂, —N(R^(a))C(O)OR^(a),—N(R^(a))C(O)R^(a), —N(R^(a))C(O)N(R^(a))₂, —N(R^(a))C(NR^(a))N(R^(a))₂,—N(R^(a))S(O)_(t)N(R^(a))₂ (where t is 1 or 2), —P(═O)(R^(a))(R^(a)), or—O—P(═O)(OR^(a))₂ where each R^(a) is independently hydrogen, alkyl,haloalkyl, carbocyclyl, carbocyclylalkyl, aryl, aralkyl,heterocycloalkyl, heterocycloalkylalkyl, heteroaryl or heteroarylalkyl,and each of these moieties can be optionally substituted as definedherein. The terms “cycloalkenyl” and “cycloalkynyl” mirror the abovedescription of “cycloalkyl” wherein the prefix “alk” is replaced with“alken” or “alkyn” respectively, and the parent “alkenyl” or “alkynyl”terms are as described herein. For example, a cycloalkenyl group canhave 3 to 13 ring atoms, such as 5 to 8 ring atoms. In some embodiments,a cycloalkynyl group can have 5 to 13 ring atoms.

As used herein, the term “halogen” refers to fluorine (F), chlorine(Cl), bromine (Br), or iodine (I). As used herein, the term “halide” or“halo”, means fluoro, chloro, bromo or iodo. The terms “haloalkyl,”“haloalkenyl,” “haloalkynyl” and “haloalkoxy” include alkyl, alkenyl,alkynyl and alkoxy structures that are substituted with one or more halogroups or with combinations thereof. For example, the terms“fluoroalkyl” and “fluoroalkoxy” include haloalkyl and haloalkoxygroups, respectively, in which the halo is fluorine, such as, but notlimited to, trifluoromethyl, difluoromethyl, 2,2,2-trifluoroethyl,1-fluoromethyl-2-fluoroethyl, and the like. Each of the alkyl, alkenyl,alkynyl and alkoxy groups are as defined herein and can be optionallyfurther substituted as defined herein.

As used herein, the term “heteroalkyl” refers to an alkyl radical, whichhave one or more skeletal chain atoms selected from an atom other thancarbon, e.g., oxygen, nitrogen, sulfur, phosphorus or combinationsthereof. A numerical range can be given, e.g., C₁₋₄ heteroalkyl, whichrefers to the chain length in total, which in this example is 4 atomslong. For example, a —CH₂OCH₂CH₃ radical is referred to as a “C₄”heteroalkyl, which includes the heteroatom center in the atom chainlength description. Connection to the parent molecular structure can bethrough either a heteroatom or a carbon in the heteroalkyl chain. Forexample, an N-containing heteroalkyl moiety refers to a group in whichat least one of the skeletal atoms is a nitrogen atom. One or moreheteroatom(s) in the heteroalkyl radical can be optionally oxidized. Oneor more nitrogen atoms, if present, can also be optionally quaternized.For example, heteroalkyl also includes skeletal chains substituted withone or more nitrogen oxide (—O—) substituents. Exemplary heteroalkylgroups include, without limitation, ethers such as methoxyethanyl(—CH₂CH₂OCH₃), ethoxymethanyl (—CH₂OCH₂CH₃), (methoxymethoxy)ethanyl(—CH₂CH₂OCH₂OCH₃), (methoxymethoxy) methanyl (—CH₂OCH₂OCH₃) and(methoxyethoxy)methanyl (—CH₂OCH₂CH₂OCH₃) and the like; amines such as(—CH₂CH₂NHCH₃, —CH₂CH₂N(CH₃)₂, —CH₂NHCH₂CH₃, —CH₂N(CH₂CH₃)(CH₃)) and thelike.

As used herein, the term “heteroaryl” or, alternatively,“heteroaromatic” refers to a refers to a radical of a 5-18 memberedmonocyclic or polycyclic (e.g., bicyclic, tricyclic, tetracyclic and thelike) aromatic ring system (e.g., having 6, 10 or 14 π electrons sharedin a cyclic array) having ring carbon atoms and 1-6 ring heteroatomsprovided in the aromatic ring system, wherein each heteroatom isindependently selected from nitrogen, oxygen, phosphorous and sulfur(“5-18 membered heteroaryl”). Heteroaryl polycyclic ring systems caninclude one or more heteroatoms in one or both rings. Whenever itappears herein, a numerical range such as “5 to 18” refers to eachinteger in the given range; e.g., “5 to 18 ring atoms” means that theheteroaryl group can consist of 5 ring atoms, 6 ring atoms, etc., up toand including 18 ring atoms. In some instances, a heteroaryl can have 5to 14 ring atoms. In some embodiments, the heteroaryl has, for example,bivalent radicals derived from univalent heteroaryl radicals whose namesend in “-yl” by removal of one hydrogen atom from the atom with the freevalence are named by adding “-ene” to the name of the correspondingunivalent radical, e.g., a pyridyl group with two points of attachmentis a pyridylene.

For example, an N-containing “heteroaromatic” or “heteroaryl” moietyrefers to an aromatic group in which at least one of the skeletal atomsof the ring is a nitrogen atom. One or more heteroatom(s) in theheteroaryl radical can be optionally oxidized. One or more nitrogenatoms, if present, can also be optionally quaternized. Heteroaryl alsoincludes ring systems substituted with one or more nitrogen oxide (—O—)substituents, such as pyridinyl N-oxides. The heteroaryl is attached tothe parent molecular structure through any atom of the ring(s).

“Heteroaryl” also includes ring systems wherein the heteroaryl ring, asdefined above, is fused with one or more aryl groups wherein the pointof attachment to the parent molecular structure is either on the aryl oron the heteroaryl ring, or wherein the heteroaryl ring, as definedabove, is fused with one or more cycloalkyl or heterocycyl groupswherein the point of attachment to the parent molecular structure is onthe heteroaryl ring. For polycyclic heteroaryl groups wherein one ringdoes not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl andthe like), the point of attachment to the parent molecular structure canbe on either ring, i.e., either the ring bearing a heteroatom (e.g.,2-indolyl) or the ring that does not contain a heteroatom (e.g.,5-indolyl). In some embodiments, a heteroaryl group is a 5-10 memberedaromatic ring system having ring carbon atoms and 1-4 ring heteroatomsprovided in the aromatic ring system, wherein each heteroatom isindependently selected from nitrogen, oxygen, phosphorous, and sulfur(“5-10 membered heteroaryl”). In some embodiments, a heteroaryl group isa 5-8 membered aromatic ring system having ring carbon atoms and 1-4ring heteroatoms provided in the aromatic ring system, wherein eachheteroatom is independently selected from nitrogen, oxygen, phosphorous,and sulfur (“5-8 membered heteroaryl”). In some embodiments, aheteroaryl group is a 5-6 membered aromatic ring system having ringcarbon atoms and 1-4 ring heteroatoms provided in the aromatic ringsystem, wherein each heteroatom is independently selected from nitrogen,oxygen, phosphorous, and sulfur (“5-6 membered heteroaryl”). In someembodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatomsselected from nitrogen, oxygen, phosphorous, and sulfur. In someembodiments, the 5-6 membered heteroaryl has 1-2 ring heteroatomsselected from nitrogen, oxygen, phosphorous, and sulfur. In someembodiments, the 5-6 membered heteroaryl has 1 ring heteroatom selectedfrom nitrogen, oxygen, phosphorous, and sulfur.

Examples of heteroaryls include, but are not limited to, azepinyl,acridinyl, benzimidazolyl, benzindolyl, 1,3-benzodioxolyl, benzofuranyl,benzooxazolyl, benzo[d]thiazolyl, benzothiadiazolyl,benzo[b][1,4]dioxepinyl, benzo[b][1,4]oxazinyl, 1,4-benzodioxanyl,benzonaphthofuranyl, benzoxazolyl, benzodioxolyl, benzodioxinyl,benzoxazolyl, benzopyranyl, benzopyranonyl, benzofuranyl,benzopyranonyl, benzofurazanyl, benzothiazolyl, benzothienyl(benzothiophenyl), benzothieno[3,2-d]pyrimidinyl, benzotriazolyl,benzo[4,6]imidazo[1,2-a]pyridinyl, carbazolyl, cinnolinyl,cyclopenta[d]pyrimidinyl,6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3-d]pyrimidinyl,5,6-dihydrobenzo[h]quinazolinyl, 5,6-dihydrobenzo[h]cinnolinyl,6,7-dihydro-5H benzo[6,7]cyclohepta[1,2-c]pyridazinyl, dibenzofuranyl,dibenzothiophenyl, furanyl, furazanyl, furanonyl, furo[3,2-c]pyridinyl,5,6,7,8,9,10-hexahydrocycloocta[d]pyrimidinyl,5,6,7,8,9,10-hexahydrocycloocta[d]pyridazinyl,5,6,7,8,9,10-hexahydrocycloocta[d]pyridinyl, isothiazolyl, imidazolyl,indazolyl, indolyl, indazolyl, isoindolyl, indolinyl, isoindolinyl,isoquinolyl, indolizinyl, isoxazolyl,5,8-methano-5,6,7,8-tetrahydroquinazolinyl, naphthyridinyl,1,6-naphthyridinonyl, oxadiazolyl, 2-oxoazepinyl, oxazolyl, oxiranyl,5,6,6a,7,8,9,10,10a-octahydrobenzo[h]quinazolinyl, 1-phenyl-1H-pyrrolyl,phenazinyl, phenothiazinyl, phenoxazinyl, phthalazinyl, pteridinyl,purinyl, pyranyl, pyrrolyl, pyrazolyl, pyrazolo[3,4-d]pyrimidinyl,pyridinyl, pyrido[3,2-d]pyrimidinyl, pyrido[3,4-d]pyrimidinyl,pyrazinyl, pyrimidinyl, pyridazinyl, pyrrolyl, quinazolinyl,quinoxalinyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl,5,6,7,8-tetrahydroquinazolinyl,5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimdinyl,6,7,8,9-tetrahydro-5H-cyclohepta[4,5]thieno[2,3-d]pyrimidinyl,5,6,7,8-tetrahydropyrido[4,5-c]pyridazinyl, thiazolyl, thiadiazolyl,thiapyranyl, triazolyl, tetrazolyl, triazinyl, thieno[2,3-d]pyrimidinyl,thieno[3,2-d]pyrimidinyl, thieno[2,3-c]pyridinyl, and thiophenyl (i.e.,thienyl). Unless stated otherwise in the specification, a heteroarylmoiety can be optionally substituted by one or more substituents whichindependently include: acyl, alkyl, alkenyl, alkynyl, alkoxy, alkylaryl,cycloalkyl, aralkyl, aryl, aryloxy, amino, amido, amidino, imino, azide,carbonate, carbamate, carbonyl, heteroalkyl, heteroaryl,heteroarylalkyl, heterocycloalkyl, hydroxy, cyano, halo, haloalkoxy,haloalkyl, ester, ether, mercapto, thio, alkylthio, arylthio,thiocarbonyl, nitro, oxo, phosphate, phosphonate, phosphinate, silyl,sulfinyl, sulfonyl, sulfonamidyl, sulfoxyl, sulfonate, urea,—Si(R^(a))₃, —OR^(a), —SR^(a), —OC(O)—R^(a), —N(R^(a))₂, —C(O)R_(a),—C(O)OR^(a), —OC(O)N(R^(a))₂, —C(O)N(R^(a))₂, —N(R^(a))C(O)OR^(a),—N(R^(a))C(O)R^(a), —N(R^(a))C(O)N(R^(a))₂, —N(R^(a))C(NR^(a))N(R^(a))₂,—N(R^(a))S(O)_(t)N(R^(a))₂ (where t is 1 or 2), —P(═O)(R^(a))(R^(a)), or—O—P(═O)(OR^(a))₂ where each R^(a) is independently hydrogen, alkyl,haloalkyl, carbocyclyl, carbocyclylalkyl, aryl, aralkyl,heterocycloalkyl, heterocycloalkylalkyl, heteroaryl or heteroarylalkyl,and each of these moieties can be optionally substituted as definedherein.

As used herein, the term “effective amount” of an active agent refers toan amount sufficient to elicit the desired biological response. As willbe appreciated by those of ordinary skill in this art, the effectiveamount of a compound of the invention may vary depending on such factorsas the desired biological endpoint, the pharmacokinetics of thecompound, the disease being treated, the mode of administration, and thepatient.

As used herein, the terms “treatment” or “treating” a disease ordisorder refers to a method of reducing, delaying or ameliorating such acondition before or after it has occurred. Treatment may be directed atone or more effects or symptoms of a disease and/or the underlyingpathology. The treatment can be any reduction and can be, but is notlimited to, the complete ablation of the disease or the symptoms of thedisease. As compared with an equivalent untreated control, suchreduction or degree of prevention is at least 5%, 10%, 20%, 40%, 50%,60%, 80%, 90%, 95%, or 100% as measured by any standard technique.

As used herein, the terms “prevent”, “preventing”, or “prevention” referto a method for precluding, delaying, averting, or stopping the onset,incidence, severity, or recurrence of a disease or condition. Forexample, a method is considered to be a prevention if there is areduction or delay in onset, incidence, severity, or recurrence of adisease or condition or one or more symptoms thereof in a subjectsusceptible to the disease or condition as compared to a subject notreceiving the method. The disclosed method is also considered to be aprevention if there is a reduction or delay in onset, incidence,severity, or recurrence of osteoporosis or one or more symptoms of adisease or condition in a subject susceptible to the disease orcondition after receiving the method as compared to the subject'sprogression prior to receiving treatment. Thus, the reduction or delayin onset, incidence, severity, or recurrence of osteoporosis can beabout a 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%, or any amount ofreduction in between.

As used herein, a “pharmaceutically acceptable form” of a disclosedcompound includes, but is not limited to, pharmaceutically acceptablesalts, esters, hydrates, solvates, isomers, prodrugs, and isotopicallylabeled derivatives thereof. In one embodiment, a “pharmaceuticallyacceptable form” includes, but is not limited to, pharmaceuticallyacceptable salts, esters, prodrugs and isotopically labeled derivativesthereof. In some embodiments, a “pharmaceutically acceptable form”includes, but is not limited to, pharmaceutically acceptable isomers andstereoisomers, prodrugs and isotopically labeled derivatives thereof.

In certain embodiments, the pharmaceutically acceptable form is apharmaceutically acceptable salt. As used herein, the term“pharmaceutically acceptable salt” refers to those salts which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of subjects without undue toxicity, irritation,allergic response and the like, and are commensurate with a reasonablebenefit/risk ratio. Pharmaceutically acceptable salts are well known inthe art. For example, Berge et al. describes pharmaceutically acceptablesalts in detail in J. Pharmaceutical Sciences (1977) 66:1-19.Pharmaceutically acceptable salts of the compounds provided hereininclude those derived from suitable inorganic and organic acids andbases. Examples of pharmaceutically acceptable, nontoxic acid additionsalts are salts of an amino group formed with inorganic acids such ashydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid andperchioric acid or with organic acids such as acetic acid, oxalic acid,maleic acid, tartaric acid, citric acid, succinic acid or malonic acidor by using other methods used in the art such as ion exchange. Otherpharmaceutically acceptable salts include adipate, alginate, ascorbate,aspartate, benzenesulfonate, besylate, benzoate, bisulfate, borate,butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate,digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate,glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate,hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate,lactate, laurate, lauryl sulfate, malate, maleate, malonate,methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate,oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate,phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate,tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts,and the like. In some embodiments, organic acids from which salts can bederived include, for example, acetic acid, propionic acid, glycolicacid, pyruvic acid, oxalic acid, lactic acid, trifluoracetic acid,maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid,citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonicacid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, andthe like.

The salts can be prepared in situ during the isolation and purificationof the disclosed compounds, or separately, such as by reacting the freebase or free acid of a parent compound with a suitable base or acid,respectively. Pharmaceutically acceptable salts derived from appropriatebases include alkali metal, alkaline earth metal, ammonium andN⁺(C₁₋₄alkyl)₄ salts. Representative alkali or alkaline earth metalsalts include sodium, lithium, potassium, calcium, magnesium, iron,zinc, copper, manganese, aluminum, and the like. Furtherpharmaceutically acceptable salts include, when appropriate, nontoxicammonium, quaternary ammonium, and amine cations formed usingcounterions such as halide, hydroxide, carboxylate, sulfate, phosphate,nitrate, lower alkyl sulfonate and aryl sulfonate. Organic bases fromwhich salts can be derived include, for example, primary, secondary, andtertiary amines, substituted amines, including naturally occurringsubstituted amines, cyclic amines, basic ion exchange resins, and thelike, such as isopropylamine, trimethylamine, diethylamine,triethylamine, tripropylamine, and ethanolamine. In some embodiments,the pharmaceutically acceptable base addition salt can be chosen fromammonium, potassium, sodium, calcium, and magnesium salts.

In certain embodiments, the pharmaceutically acceptable form is a“solvate” (e.g., a hydrate). As used herein, the term “solvate” refersto compounds that further include a stoichiometric or non-stoichiometricamount of solvent bound by non-covalent intermolecular forces. Thesolvate can be of a disclosed compound or a pharmaceutically acceptablesalt thereof. Where the solvent is water, the solvate is a “hydrate”.Pharmaceutically acceptable solvates and hydrates are complexes that,for example, can include 1 to about 100, or 1 to about 10, or 1 to about2, about 3 or about 4, solvent or water molecules. It will be understoodthat the term “compound” as used herein encompasses the compound andsolvates of the compound, as well as mixtures thereof.

In certain embodiments, the pharmaceutically acceptable form is aprodrug. As used herein, the term “prodrug” (or “pro-drug”) refers tocompounds that are transformed in vivo to yield a disclosed compound ora pharmaceutically acceptable form of the compound. A prodrug can beinactive when administered to a subject, but is converted in vivo to anactive compound, for example, by hydrolysis (e.g., hydrolysis in blood).In certain cases, a prodrug has improved physical and/or deliveryproperties over the parent compound. Prodrugs can increase thebioavailability of the compound when administered to a subject (e.g., bypermitting enhanced absorption into the blood following oraladministration) or which enhance delivery to a biological compartment ofinterest (e.g., the brain or lymphatic system) relative to the parentcompound. Exemplary prodrugs include derivatives of a disclosed compoundwith enhanced aqueous solubility or active transport through the gutmembrane, relative to the parent compound.

The prodrug compound often offers advantages of solubility, tissuecompatibility or delayed release in a mammalian organism (see, e.g.,Bundgard, H., Design of Prodrugs (1985), pp. 7-9, 21-24 (Elsevier,Amsterdam). A discussion of prodrugs is provided in Higuchi, T., et al.,“Pro-drugs as Novel Delivery Systems,” A.C.S. Symposium Series, Vol. 14,and in Bioreversible Carriers in Drug Design, ed. Edward B. Roche,American Pharmaceutical Association and Pergamon Press, 1987, both ofwhich are incorporated in full by reference herein. Exemplary advantagesof a prodrug can include, but are not limited to, its physicalproperties, such as enhanced water solubility for parenteraladministration at physiological pH compared to the parent compound, orit can enhance absorption from the digestive tract, or it can enhancedrug stability for long-term storage.

As used herein, the term “pharmaceutically acceptable” excipient,carrier, or diluent refers to a pharmaceutically acceptable material,composition or vehicle, such as a liquid or solid filler, diluent,excipient, solvent or encapsulating material, involved in carrying ortransporting the subject pharmaceutical agent from one organ, or portionof the body, to another organ, or portion of the body. Each carrier mustbe “acceptable” in the sense of being compatible with the otheringredients of the formulation and not injurious to the patient. Someexamples of materials which can serve as pharmaceutically-acceptablecarriers include: sugars, such as lactose, glucose and sucrose;starches, such as corn starch and potato starch; cellulose, and itsderivatives, such as sodium carboxymethyl cellulose, ethyl cellulose andcellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients,such as cocoa butter and suppository waxes; oils, such as peanut oil,cottonseed oil, safflower oil, sesame oil, olive oil, corn oil andsoybean oil; glycols, such as propylene glycol; polyols, such asglycerin, sorbitol, mannitol and polyethylene glycol; esters, such asethyl oleate and ethyl laurate; agar; buffering agents, such asmagnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-freewater; isotonic saline; Ringer's solution; ethyl alcohol; phosphatebuffer solutions; and other non-toxic compatible substances employed inpharmaceutical formulations. Wetting agents, emulsifiers and lubricants,such as sodium lauryl sulfate, magnesium stearate, and polyethyleneoxide-polypropylene oxide copolymer as well as coloring agents, releaseagents, coating agents, sweetening, flavoring and perfuming agents,preservatives and antioxidants can also be present in the compositions.

As used herein, the terms “isolated” or “purified” refer to a materialthat is substantially or essentially free from components that normallyaccompany it in its native state. Purity and homogeneity are typicallydetermined using analytical chemistry techniques such as polyacrylamidegel electrophoresis or high performance liquid chromatography.

As used herein, the term “subject” refers to any animal (e.g., amammal), including, but not limited to humans, non-human primates,rodents, and the like, which is to be the recipient of a particulartreatment. Typically, the terms “subject” and “patient” are usedinterchangeably herein in reference to a human subject.

As used herein, the term “low dosage” refers to at least 5% less (e.g.,at least 10%, 20%, 50%, 80%, 90%, or even 95%) than the lowest standardrecommended dosage of a particular compound formulated for a given routeof administration for treatment of any human disease or condition. Forexample, a low dosage of an agent that is formulated for administrationby inhalation will differ from a low dosage of the same agent formulatedfor oral administration.

As used herein, the term “high dosage” is meant at least 5% (e.g., atleast 10%, 20%, 50%, 100%, 200%, or even 300%) more than the higheststandard recommended dosage of a particular compound for treatment ofany human disease or condition.

As used herein, the term “prodrug” (or “pro-drug”) refers to apharmacological derivative of a parent drug molecule that requiresbiotransformation, either spontaneous or enzymatic, within the organismto release the active drug. Such prodrugs are pharmaceutically active invivo, when they undergo solvolysis under physiological conditions orundergo enzymatic degradation. Prodrug compounds herein may be calledsingle, double, triple, etc., depending on the number ofbiotransformation steps required to release the active drug within theorganism, and the number of functionalities present in a precursor-typeform.

Prodrug forms often offer advantages of solubility, tissuecompatibility, or delayed release in the mammalian organism. (See,Bundgard, Design of Prodrugs, pp. 7-9, 21-24, Elsevier, Amsterdam 1985and Silverman, The Organic Chemistry of Drug Design and Drug Action, pp.352-401, Academic Press, San Diego, Calif., 1992). Prodrugs commonlyknown in the art include well-known acid derivatives, such as, forexample, esters prepared by reaction of the parent acids with a suitablealcohol, amides prepared by reaction of the parent acid compound with anamine, basic groups reacted to form an acylated base derivative, etc. Ofcourse, other prodrug derivatives may be combined with other featuresdisclosed herein to enhance bioavailability. As such, those of skill inthe art will appreciate that certain of the presently disclosedcompounds having free amino, amido, hydroxy or carboxylic groups can beconverted into prodrugs. Prodrugs include compounds having an amino acidresidue, or a polypeptide chain of two or more (e.g., two, three orfour) amino acid residues which are covalently joined through peptidebonds to free amino, hydroxy or carboxylic acid groups of the presentlydisclosed compounds. The amino acid residues include the 20 naturallyoccurring amino acids commonly designated by three letter symbols andalso include 4-hydroxyproline, hydroxylysine, demosine, isodemosine,3-methylhistidine, norvaline, beta-alanine, gamma-aminobutyric acid,citrulline homocysteine, homoserine, ornithine and methionine sulfone.Prodrugs also include compounds having a carbonate, carbamate, amide oralkyl ester moiety covalently bonded to any of the above substituentsdisclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

The invention is based on an unexpected discovery of a novel class oforally available, selective and potent HCV therapeutics that are lesssusceptible to drug resistance than existing therapeutics. The inventionalso provides pharmaceutical compositions of these compounds and methodsof preparation and use thereof. The macrocyclic HCV NS3/4A proteaseinhibitors disclosed herein exhibited exceptional potency profiles withEC₅₀ values less than 5 nM against major drug resistant HCV variants.

Without wishing to be bound by the theory, the HCV NS3/4A PIs disclosedherein are less susceptible to drug resistance at least in part due totheir interaction with evolutionarily constrained regions of theprotease while avoiding interactions with residues not essential forsubstrate recognition.

Specifically, these macrocyclic inhibitors incorporate flexiblequinoxalines at the P2 position. Investigation of structure-activityrelationships showed that the P2 quinoxalines with small hydrophobicsubstituents at the 3-position were better for maintaining potencyagainst drug resistant variants, likely due to reduced interactions withresidues in the S2 subsite. In contrast, inhibitors with larger groupsat this position were highly susceptible to mutations at Arg155, Ala156and Asp168.

Drug resistance is a major problem across all DAA classes targeting HCV.As new therapies are developed the potential for drug resistance must beminimized at the outset of inhibitor design. The substrate envelopemodel provides a rational approach to design robust NS3/4A PIs withimproved resistance profiles.

The present inventors previously determined the molecular mechanisms ofdrug resistance due to single site mutations by solving high-resolutioncrystal structures of PIs bound to WT and mutant proteases. Thesecrystal structures revealed that the large heterocyclic P2 moieties ofPIs bind outside the substrate-binding region, defined as the substrateenvelope, and make extensive interactions with residues Arg155, Ala156and Asp168. The inhibitor P2 moiety induces an extended S2 subsite byforcing the Arg155 side chain to rotate nearly 180° relative to itsconformation in substrate complexes. This altered Arg155 conformation isstabilized by electrostatic interactions with Asp168, providingadditional hydrophobic surface that is critical for efficient inhibitorbinding. Disruption of electrostatic interactions between Arg155 andAsp168 due to mutations underlies drug resistance against NS3/4A PIs.Moreover, it has been shown that structural differences at the P2 moietylargely determine the resistance profile of these inhibitors. (Romano,et al. Proc. Natl. Acad. Sci. U.S.A 2010, 107, 20986-20991; Romano, etal. PLOS Pathog. 2012, 8, e1002832; Soumana, et al. ACS Chem. Biol.2014, 9, 2485-2490; Soumana, et al. J. Am. Chem. Soc. 2016, 138,11850-11859; O'Meara, et al. J. Biol. Chem. 2013, 288, 5673-5681; Ali,et al. ACS Chem. Biol. 2013, 8, 1469-1478.)

MK-5172 (1), a potent HCV NS3/4A PI, has a unique binding mode where theP2 quinoxaline moiety interacts with residues of the catalytic triad,avoiding direct interactions with Arg155 and Asp168 (FIG. 2 ). As aresult, 1 has an excellent potency profile across different genotypesand relatively low susceptibility to drug resistance due to mutations atArg155 and Asp168. (Romano, et al. PLOS Pathog. 2012, 8, e1002832;Summa, et al. Antimicrob. Agents Chemother. 2012, 56, 4161-4167.)

However, 1 is highly susceptible to mutations at Ala156, mainly due tosteric clashes of larger side chains with the P2-P4 macrocycle. It hasbeen shown that the P1-P3 macrocyclic analogue 5172-mcP1P3 (2) avoidsthis steric clash while still maintaining the unique binding mode of 1(FIG. 2 ). Compound 2, though slightly less potent than 1 against WTHCV, has an excellent potency profile with EC₅₀ values in the singledigit nanomolar range against drug resistant variants including A156T.Similar to 1, the P2 quinoxaline moiety in 2 stacks against thecatalytic residues His57 and Asp81 and largely avoids directinteractions with residues around the S2 subsite. Unlike 1, the flexibleP2 quinoxaline moiety in 2 better accommodates mutations at Ala156,resulting in an overall improved resistance profile. (Ali, et al. ACSChem. Biol. 2013, 8, 1469-1478; Soumana, et al. ACS Chem. Biol. 2016,11, 900-909.)

SAR studies led the present inventors to believe that reducing PIinteractions with residues in the S2 subsite is important to achieveinhibitors with exceptional potency and resistance profiles.Specifically, the P1-P3 macrocyclic inhibitors incorporating flexible P2quinoxaline moieties bearing small hydrophobic groups at the 3-positionmaintain excellent potency in both enzymatic and antiviral assaysagainst drug resistant variants.

Without wishing to be bound by the theory, these inhibitors leverageinteractions with the essential catalytic triad residues and avoiddirect contacts with residues that can mutate to confer resistance.Moreover, conformational flexibility at the P2 moiety is important toefficiently accommodate structural changes due to mutations in the S2pocket in order to avoid resistance. These insights provide strategiesfor iterative rounds of inhibitor design with the paradigm thatdesigning inhibitors with flexible P2 quinoxalines, leveragingevolutionarily constrained areas in the protease active site andexpanding into the substrate envelope may provide inhibitors that arerobust against drug resistant variants.

Modifications were also made at the P4-P5 positions to utilizeunexploited space in the SE. Hydrophobic moieties at the P4 positionwere used to mimic substrate interactions, as HCV substrates acrossgenotypes have hydrophobic residues at this position.

In one aspect, the invention generally relates to a compound having thestructural formula (I),

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof.

In certain embodiments, each of R⁷, R′⁷, R″⁷ is independently a C₁-C₆alkyl group (e.g., methyl, ethyl, propyl, i-propyl). In certainembodiments, each of R⁷, R′⁷, R″⁷ is a methyl group.

In certain embodiments, at least one of R⁶ and R′⁶ is H. In certainembodiments, both of R⁶ and R′⁶ is H.

In certain embodiments, X is O and Y is N, the compound has thestructural formula:

In certain embodiments, R¹ is at the 7-position and the compound has thestructural formula:

In certain embodiments, R¹ is H. In certain embodiments, R^(p) is aC₁-C₆ alkoxy group. In certain embodiments, R¹ is a C₁-C₂ alkoxy (e.g.,methoxy, ethoxy).

In certain embodiments, R² is a C₁-C₆ alkyl group (e.g., methyl, ethyl,propyl, i-propyl). In certain embodiments, R² is a halogen (e.g., F,Cl). In certain embodiments, R² is an aryl group. In certainembodiments, R² is 2-thiophene.

In certain embodiments, R³ is H. In certain embodiments, R³ is a C₁-C₆alkyl group (e.g., methyl, ethyl, propyl, i-propyl). In certainembodiments, R³ is a C₁-C₂ alkyl group.

In certain embodiments, R⁴ is a C₁-C₆ alkyl group (e.g., methyl, ethyl,propyl, i-propyl). In certain embodiments, R⁴ is a branched C₃-C₆ alkylgroup. In certain embodiments, R⁴ is a C₃-C₆ cycloalkyl group.

In certain embodiments, the compound is selected from:

In another aspect, the invention generally relates to a compound havingthe structural formula (II),

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof.

In certain embodiments, the compound has the structural formula (IIa),

In certain embodiments, each of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ is H andthe compound has the structural formula (IIb),

In certain embodiments of the compound of formula (II), R¹ is at the7-position, having the structural formula (III),

In certain embodiments, R³ is H.

In certain embodiments, R³ is a C₁-C₆ alkyl group. In certainembodiments, R³ is a C₁-C₂ alkyl group (e.g., methyl, ethyl).

In certain embodiments, R¹ is H.

In certain embodiments, R¹ is a C₁-C₆ alkoxy group. In certainembodiments, R¹ is a C₁-C₂ alkoxy (e.g., methoxy, ethoxy).

In certain embodiments, R² is a C₁-C₆ alkyl group (e.g., methyl, ethyl,propyl, i-propyl).

In certain embodiments, R² is a halogen (e.g., F, Cl).

In certain embodiments, R² is an aryl group (e.g., thiophene).

In certain embodiments, R⁴ is a C₁-C₆ alkyl group. In certainembodiments, R⁴ is a C₁-C₄ alkyl group (e.g., methyl, ethyl, propyl,i-propyl). In certain embodiments, R⁴ is a branched C₃ or C₄ alkylgroup. In certain embodiments, R⁴ is a linear C₃ or C₄ alkyl group. Incertain embodiments, R⁴ is a C₃, C₄, C₅ or C₆ cycloalkyl group having a3-, 4-, 5-, or 6-membered ring.

Exemplary compounds include:

In yet another aspect, the invention generally relates to a compoundhaving the structural formula (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof.

In certain embodiments, R¹² is a C₁-C₆ alkyl (e.g., methyl, ethyl,propyl, i-propyl). In certain embodiments, R¹² is a C₂-C₄ alkyl. Incertain embodiments, R¹² is a linear or branched C₃ alkyl.

In certain embodiments, R¹³ is a C₁-C₆ alkyl (e.g., methyl, ethyl,propyl, i-propyl).

In certain embodiments, each of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ is H.

In certain embodiments, R¹ is at the 7-position. In certain embodiments,R¹ is H. In certain embodiments, R¹ is a C₁-C₆ alkoxy group (e.g.,methoxy, ethoxy). In certain embodiments, R¹ is a C₁-C₂ alkoxy.

In certain embodiments, R² is a C₁-C₆ alkyl group (e.g., methyl, ethyl,propyl, i-propyl). In certain embodiments, R² is a halogen (e.g., F,Cl). In certain embodiments, R² is an aryl group. In certainembodiments, R² is 2-thiophene.

In certain embodiments, R³ is H. In certain embodiments, R³ is a C₁-C₆alkyl group (e.g., methyl, ethyl, propyl, i-propyl). In certainembodiments, R³ is a C₁-C₂ alkyl group.

In certain embodiments, the compound is selected from:

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound having the structuralformula of (I):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof, effective to treat orreduce HCV infection or a related disease or disorder, in a mammal,including a human, and a pharmaceutically acceptable excipient, carrier,or diluent.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound having the structuralformula of (II):

wherein

each of X and Y is independently selected from O, NH and CH₂, providedthat at least one of X and Y is NH;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group, wherein each R is independently aH or an alkyl group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;and

each R¹¹ is independently selected from H, halogen, or an alkyl group,

or a pharmaceutically acceptable form thereof, effective to treat orreduce HCV infection or a related disease or disorder, in a mammal,including a human, and a pharmaceutically acceptable excipient, carrier,or diluent.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound having the structuralformula of (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof, effective to treat orreduce HCV infection or a related disease or disorder, in a mammal,including a human, and a pharmaceutically acceptable excipient, carrier,or diluent.

In yet another aspect, the invention generally relates to apharmaceutical composition comprising a compound disclosed herein.

In certain embodiments, the pharmaceutical composition is effective totreat or reduce an HCV infection of a Genotype 1 (GT1) or genotype 3(GT3). In certain embodiments, the HCV infection is a genotype 1 (GT1)infection. In certain embodiments, the HCV infection is a genotype 3(GT3) infection.

In certain embodiments, the pharmaceutical composition is effective totreat or reduce HCV infection comprising D168A/V mutations.

The pharmaceutical composition of the invention may be comprised of anyof the protease inhibitor or inactivator herein disclosed.

In yet another aspect, the invention generally relates to a unit dosage.The unit dosage form is comprised of a pharmaceutical herein disclosed.

In certain embodiments, the unit dosage is in the form of a tablet orcapsule suitable for oral administration.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder.The method includes: administering to a subject in need thereof apharmaceutical composition comprising a compound having the structuralformula of (I):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder.The method includes: administering to a subject in need thereof apharmaceutical composition comprising a compound having the structuralformula of (II):

wherein

each of X and Y is independently selected from O, NH and CH₂, providedthat at least one of X and Y is NH;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group, wherein each R is independently aH or an alkyl group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;and

each R¹¹ is independently selected from H, halogen, or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder.The method includes: administering to a subject in need thereof apharmaceutical composition comprising a compound having the structuralformula of (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method fortreating or reducing HCV infection, or a related disease or disorder,comprising administering to a subject in need thereof a pharmaceuticalcomposition or a unit dosage form disclosed herein.

In certain embodiments, the method is effective to treat or reduce anHCV infection of a Genotype 1 (GT1) or genotype 3 (GT3). In certainembodiments, the HCV infection is a genotype 1 (GT1) infection. Incertain embodiments, the HCV infection is a genotype 3 (GT3) infection.

In certain embodiments, the method is effective to treat or reduce HCVinfection comprising D168A/V mutations.

In certain embodiments, the method further includes administering to thesubject one or more other anti-viral agents.

The one or more other anti-viral agents are selected any suitableanti-viral agents, for example, polymerase inhibitors.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositioncomprising a compound having the structural formula of (I):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶, R′⁶ each is independently H, halogen, or an alkyl group;

R⁷, R′⁷, R″⁷ each is independently H, halogen, or an alkyl group;

R⁸ is independently selected from H, halogen, or an alkyl group;

each R and R′ is independently a H or an alkyl group; and

provided that R′⁶ and one of R′⁷ and R″⁷ optionally join together toform a 15-, 16- or 17-membered ring,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositioncomprising a compound having the structural formula of (II):

wherein

each of X and Y is independently selected from 0, NH and CH₂, providedthat at least one of X and Y is NH;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group, wherein each R is independently aH or an alkyl group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;and

each R¹¹ is independently selected from H, halogen, or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositioncomprising a compound having the structural formula of (IV):

wherein

each of X and Y is independently selected from O, NR and CRR′, providedthat at least one of X and Y is NR;

R¹ is selected from H, a C₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen,—(C═O)N—R, —N(C═O)R, —(SO₂)NR₂ group;

R² is selected from H, halogen, a C₁-C₆ alkyl, aryl, —CN, CF₃, CHF₂,CH₂F;

R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;

R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R;

R⁵ is H, halogen, or an alkyl group;

R⁶ is H, halogen, or an alkyl group;

R⁷ is H, halogen, or an alkyl group;

each R⁸ is independently selected from H, halogen, or an alkyl group;

each R⁹ is independently selected from H, halogen, or an alkyl group;

each R¹⁰ is independently selected from H, halogen, or an alkyl group;

each R¹¹ is independently selected from H, halogen, or an alkyl group;

R¹² is H, halogen, or an alkyl group;

R¹³ is H, halogen, an alkyl group, hetero-alkyl, aryl, or hetero-arylgroup; and

each R and R′ is independently a H or an alkyl group,

or a pharmaceutically acceptable form thereof, and a pharmaceuticallyacceptable excipient, carrier, or diluent.

In yet another aspect, the invention generally relates to a method forinhibiting or inactivating HCV NS3/4A protease. The method includes:administering to a subject in need thereof a pharmaceutical compositiondisclosed herein.

In certain embodiments, the HCV NS3/4A protease is a wild-type protease.

In certain embodiments, the HCV NS3/4A protease is a mutant variant ofthe wild-type protease.

In certain embodiments, the subject does not develop resistance to acompound of the invention after extended time of administration of thecompound.

Isotopically-labeled compounds are also within the scope of the presentdisclosure. As used herein, an “isotopically-labeled compound” refers toa presently disclosed compound including pharmaceutical salts andprodrugs thereof, each as described herein, in which one or more atomsare replaced by an atom having an atomic mass or mass number differentfrom the atomic mass or mass number usually found in nature. Examples ofisotopes that can be incorporated into compounds presently disclosedinclude isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous,fluorine and chlorine, such as ²H, ³H, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, ³¹P,³²P, ³⁵S, ¹⁸F, and ³⁶Cl, respectively.

By isotopically-labeling the presently disclosed compounds, thecompounds may be useful in drug and/or substrate tissue distributionassays. Tritiated (³H) and carbon-14 (¹⁴C) labeled compounds areparticularly preferred for their ease of preparation and detectability.Further, substitution with heavier isotopes such as deuterium (²H) canafford certain therapeutic advantages resulting from greater metabolicstability, for example increased in vivo half-life or reduced dosagerequirements and, hence, may be preferred in some circumstances.Isotopically labeled compounds presently disclosed, includingpharmaceutical salts, esters, and prodrugs thereof, can be prepared byany means known in the art.

Further, substitution of normally abundant hydrogen (¹H) with heavierisotopes such as deuterium can afford certain therapeutic advantages,e.g., resulting from improved absorption, distribution, metabolismand/or excretion (ADIE) properties, creating drugs with improvedefficacy, safety, and/or tolerability. Benefits may also be obtainedfrom replacement of normally abundant C with ¹³C. (See, WO 2007/005643,WO 2007/005644, WO 2007/016361, and WO 2007/016431.)

Stereoisomers (e.g., cis and trans isomers) and all optical isomers of apresently disclosed compound (e.g., R and S enantiomers), as well asracemic, diastereomeric and other mixtures of such isomers are withinthe scope of the present disclosure.

Compounds of the present invention are, subsequent to their preparation,preferably isolated and purified to obtain a composition containing anamount by weight equal to or greater than 95% (“substantially pure”),which is then used or formulated as described herein. In certainembodiments, the compounds of the present invention are more than 99%pure.

Solvates and polymorphs of the compounds of the invention are alsocontemplated herein. Solvates of the compounds of the present inventioninclude, for example, hydrates.

Any appropriate route of administration can be employed, for example,parenteral, intravenous, subcutaneous, intramuscular, intraventricular,intracorporeal, intraperitoneal, rectal, or oral administration. Mostsuitable means of administration for a particular patient will depend onthe nature and severity of the disease or condition being treated or thenature of the therapy being used and on the nature of the activecompound.

Solid dosage forms for oral administration include capsules, tablets,pills, powders, and granules. In such solid dosage forms, the compoundsdescribed herein or derivatives thereof are admixed with at least oneinert customary excipient (or carrier) such as sodium citrate ordicalcium phosphate or (i) fillers or extenders, as for example,starches, lactose, sucrose, glucose, mannitol, and silicic acid, (ii)binders, as for example, carboxymethylcellulose, alignates, gelatin,polyvinylpyrrolidone, sucrose, and acacia, (iii) humectants, as forexample, glycerol, (iv) disintegrating agents, as for example,agar-agar, calcium carbonate, potato or tapioca starch, alginic acid,certain complex silicates, and sodium carbonate, (v) solution retarders,as for example, paraffin, (vi) absorption accelerators, as for example,quaternary ammonium compounds, (vii) wetting agents, as for example,cetyl alcohol, and glycerol monostearate, (viii) adsorbents, as forexample, kaolin and bentonite, and (ix) lubricants, as for example,talc, calcium stearate, magnesium stearate, solid polyethylene glycols,sodium lauryl sulfate, or mixtures thereof. In the case of capsules,tablets, and pills, the dosage forms may also comprise buffering agents.Solid compositions of a similar type may also be employed as fillers insoft and hard-filled gelatin capsules using such excipients as lactoseor milk sugar as well as high molecular weight polyethyleneglycols, andthe like. Solid dosage forms such as tablets, dragees, capsules, pills,and granules can be prepared with coatings and shells, such as entericcoatings and others known in the art.

Liquid dosage forms for oral administration include pharmaceuticallyacceptable emulsions, solutions, suspensions, syrups, and elixirs. Inaddition to the active compounds, the liquid dosage forms may containinert diluents commonly used in the art, such as water or othersolvents, solubilizing agents, and emulsifiers, such as for example,ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzylalcohol, benzyl benzoate, propyleneglycol, 1,3-butyleneglycol,dimethylformamide, oils, in particular, cottonseed oil, groundnut oil,corn germ oil, olive oil, castor oil, sesame oil, glycerol,tetrahydrofurfuryl alcohol, polyethyleneglycols, and fatty acid estersof sorbitan, or mixtures of these substances, and the like. Besides suchinert diluents, the composition can also include additional agents, suchas wetting, emulsifying, suspending, sweetening, flavoring, or perfumingagents.

Materials, compositions, and components disclosed herein can be usedfor, can be used in conjunction with, can be used in preparation for, orare products of the disclosed methods and compositions. It is understoodthat when combinations, subsets, interactions, groups, etc. of thesematerials are disclosed that while specific reference of each variousindividual and collective combinations and permutations of thesecompounds may not be explicitly disclosed, each is specificallycontemplated and described herein. For example, if a method is disclosedand discussed and a number of modifications that can be made to a numberof molecules including in the method are discussed, each and everycombination and permutation of the method, and the modifications thatare possible are specifically contemplated unless specifically indicatedto the contrary. Likewise, any subset or combination of these is alsospecifically contemplated and disclosed. This concept applies to allaspects of this disclosure including, but not limited to, steps inmethods using the disclosed compositions. Thus, if there are a varietyof additional steps that can be performed, it is understood that each ofthese additional steps can be performed with any specific method stepsor combination of method steps of the disclosed methods, and that eachsuch combination or subset of combinations is specifically contemplatedand should be considered disclosed.

Certain compounds of the present invention may exist in particulargeometric or stereoisomeric forms. The present invention contemplatesall such compounds, including cis- and trans-isomers, R- andS-enantiomers, diastereomers, (D)-isomers, (L)-isomers, the racemicmixtures thereof, and other mixtures thereof, as falling within thescope of the invention. Additional asymmetric carbon atoms may bepresent in a substituent such as an alkyl group. All such isomers, aswell as mixtures thereof, are intended to be included in this invention.

Isomeric mixtures containing any of a variety of isomer ratios may beutilized in accordance with the present invention. For example, whereonly two isomers are combined, mixtures containing 50:50, 60:40, 70:30,80:20, 90:10, 95:5, 96:4, 97:3, 98:2, 99:1, or 100:0 isomer ratios arecontemplated by the present invention. Those of ordinary skill in theart will readily appreciate that analogous ratios are contemplated formore complex isomer mixtures.

If, for instance, a particular enantiomer of a compound of the presentinvention is desired, it may be prepared by asymmetric synthesis, or byderivation with a chiral auxiliary, where the resulting diastereomericmixture is separated and the auxiliary group cleaved to provide the puredesired enantiomers. Alternatively, where the molecule contains a basicfunctional group, such as amino, or an acidic functional group, such ascarboxyl, diastereomeric salts are formed with an appropriateoptically-active acid or base, followed by resolution of thediastereomers thus formed by fractional crystallization orchromatographic methods well known in the art, and subsequent recoveryof the pure enantiomers.

Examples

Herein described is a substrate envelope-guided strategy that led to thedesign of NS3/4A PIs with exceptional potency profiles against majordrug resistant HCV variants.

Part 1. P1-P3 Macrocyclic Inhibitors

A series of analogues were designed and synthesized with diversesubstituents at the 3-position of P2 quinoxaline moiety. Investigationof structure-activity relationships (SARs) identified P2 quinoxalinederivatives that predominantly interact with the invariant catalytictriad and avoid contacts with the S2 subsite residues. Inhibitors withsmall hydrophobic substituents at the 3-position of P2 quinoxalinemaintained better potency against drug resistant variants, likely due toreduced interactions with residues in the S2 subsite. A novel class ofHCV therapeutics was achieved that are safe and effective HCV NS3/4Aprotease inhibitors and are less susceptible to drug resistance thanexisting therapeutics.

Structure-Guided SAR Investigation and Compound Design

From structure-guided SAR investigations, compound 2 was identified as astarting point for modification due to its unique structural features:(1) the P2 quinoxaline moiety that predominantly interacts with thehighly conserved catalytic residues Asp81 and His57 and (2) theconformational flexibility that allows the inhibitor to efficientlyaccommodate structural changes in the S2 subsite due to resistancemutations.

Identifying and optimizing substituents at the P2 quinoxaline and theN-terminal capping remains challenging in discerning analogues withimproved potency and resistance profiles. To address the challenge,efforts were focused on exploration of SARs at the P2 quinoxaline moietyin 2, for example, substituting the ethyl group at the 3-position thatdirectly interacts with protease S2 subsite residues Arg155 and Ala156.The SAR strategy was based on insights from detailed structural analysisof 1 and 2 bound to wild-type NS3/4A protease and drug resistantvariants.

A series of inhibitors with diverse substituents at the 3-position of P2quinoxaline were designed and synthesized. In particular, SARinformation based on these compounds was used to investigate whethersmall hydrophobic groups at the 3-position of the quinoxaline would bepreferred for retaining inhibitor potency against drug resistantvariants as larger groups that make extensive interactions with Arg155,Ala156 and Asp168 would result in inhibitors highly susceptible tomutations at these positions.

The potency and resistance profiles of NS3/4A PIs were assessed usingbiochemical and replicon assays. The enzyme inhibition constants (Ki)were determined against wild-type GT1a NS3/4A protease, drug-resistantvariant D168A, and GT3a NS3/4A protease (Table 1). The cellularantiviral potencies (EC₅₀) were determined using HCV replicon-basedantiviral assays against wild-type and drug-resistant variants R155K,A156T, D168A, and D168V (Table 2). Compound 1 was used as a control inall assays.

TABLE 1 Inhibitory activity against wild-type NS3/4A protease and drugresistant variants

Ki (nM) GT1a WT NS3/4A GT1a D168A GT3a NS3/4A Inhibitor R¹ R² R³Protease NS3/4A Protease Protease 2 OMe Et H 3.29 ± 0.52 82.4 ± 4.4 204± 19 19a OMe Et Me 1.82 ± 0.38 55.2 ± 5.3 171 ± 23 22a OMe Et H 1.24 ±0.14 52.3 ± 3.2 211 ± 18 23a OMe Et Me 1.37 ± 0.34 55.2 ± 5.3 186 ± 3018b OMe Me H 3.40 ± 0.47 50.9 ± 3.7 152 ± 18 19b OMe Me Me 3.60 ± 0.4452.0 ± 2.4 119 ± 18 22b OMe Me H 0.93 ± 0.15 31.9 ± 2.5 147 ± 20 23b OMeMe Me 1.13 ± 0.22 36.3 ± 1.8 121 ± 16 18c OMe Cl H 1.07 ± 0.17 39.8 ±3.4 67.5 ± 8.0 19c OMe Cl Me 1.11 ± 0.38 77.7 ± 6.1 53.6 ± 5.9 22c OMeCl H 0.49 ± 0.15 30.6 ± 2.6 85.6 ± 11  23c OMe Cl Me 0.44 ± 0.15 25.7 ±1.8 61.0 ± 12  18d OMe CF₃ H 13.3 ± 3.9  157 ± 12  344 ± 141 19d OMe CF₃Me 5.77 ± 1.78 118 ± 13 231 ± 74 22d OMe CF₃ H 7.55 ± 2.39 115 ± 12  757± 334 23d OMe CF₃ Me 8.14 ± 2.37 110 ± 14  433 ± 206 18e OMe i-Pr H 4.27± 1.34 239 ± 20 NT 19e OMe i-Pr Me 0.58 ± 0.08 211 ± 19 NT 22e OMe i-PrH 1.44 ± 0.46 161 ± 11 NT 23e OMe i-Pr Me 1.34 ± 0.48 156 ± 17 NT 18f H2- H 1.03 ± 0.13 1823 ± 347 NT thiophene 22f H 2- H 1.59 ± 0.56 900 ± 81NT thiophene 18g H Et H 7.18 ± 1.02 190 ± 13 NT 22g H Et H 1.99 ± 0.48 107 ± 7.0 NT MK-5172 (1) 0.21 ± 0.03 49.1 ± 1.6 30.3 ± 1.9

TABLE 2 Antiviral activity against wild-type HCV and drug resistantvariants

Replicon EC₅₀ (nM) Inhibitor R¹ R² R³ WT R155K A156T D168A D168V 2 OMeEt H 0.33  1.75   9.65   6.31   9.10 19a OMe Et Me 0.43  1.80   4.52  4.97   6.42 22a OMe Et H 0.14  2.08  11.8    3.60  11.9  23a OMe Et Me0.16  2.07  10.6    3.45   7.08 18b OMe Me H 0.39  1.17   5.95   4.24  3.17 19b OMe Me Me 0.30  0.80   1.57   2.37   1.60 22b OMe Me H 0.11 0.89   2.88   2.63   4.32 23b OMe Me Me 0.13  1.09   3.99   2.16   2.8518c OMe Cl H 0.16  0.44  16.2    1.42   0.73 19c OMe Cl Me 0.18  0.40  8.86   1.07   0.49 22c OMe Cl H 0.15  0.59   3.55   1.32   1.55 23cOMe Cl Me 0.15  0.56   4.32   0.97   1.09 18d OMe CF₃ H 1.98  3.45 36.2   16.8   17.1  19d OMe CF₃ Me 1.52  2.30  20.5    8.64   8.31 22dOMe CF₃ H 4.86  7.97 117     15.1   24.0  23d OMe CF₃ Me 4.04  6.90 75.9    8.46  11.4  18e OMe i-Pr H 1.43  5.02  25.7   15.3   23.7  19eOMe i-Pr Me 1.86  4.14  21.2   11.9   18.1  22e OMe i-Pr H 0.48  7.63 32.1    7.96  30.1  23e OMe i-Pr Me 0.59  6.83  27.6    7.91  18.2  18fH 2-thiophene H 0.98 21.7  256    111    193    22f H 2-thiophene H 0.4019.2  183     42.2   70.0  18g H Et H 0.46  1.81  10.6    8.55  14.0 22g H Et H 0.24  4.28  24.6    7.50  19.3  MK-5172 (1) 0.14  1.89 238     9.69   5.41

Compound 1 showed sub-nanomolar inhibitory potency against WT NS3/4Aprotease and maintained nanomolar activity against drug resistantvariant D168A and GT3a protease. Similarly, in replicon assays 1exhibited an excellent potency profile with sub-nanomolar activityagainst WT HCV (EC₅₀=0.14 nM) and low nanomolar activity against drugresistant variants R155K, D168A, and D168V. However, in line withprevious reports, 1 was highly susceptible to the A156T mutation(EC₅₀=238 nM), losing over 1000-fold potency against this variant. (Ali,et al. ACS Chem. Biol. 2013, 8, 1469-1478.)

Compared to 1, the P1-P3 macrocyclic analogue 2 exhibited lowerinhibitory potency against WT protease and the D168A variant. Also, theinhibitory activity of 2 against the GT3a protease was considerablylower than that of 1. Compound 2 displayed a superior potency profile inreplicon assays with sub-nanomolar activity against WT HCV (EC₅₀=0.33nM) and maintained single digit nanomolar potency against alldrug-resistant variants tested. Notably, unlike 1, compound 2 maintainedlow nanomolar potency against the A156T variant (EC₅₀=9.65 nM). Thus,with an improved resistance profile compared to 1, the P1-P3 macrocyclicanalogue 2 is an attractive lead compound for further optimization.(Ali, et al. ACS Chem. Biol. 2013, 8, 1469-1478.)

Modifications of P1′ and P4 Capping Groups

Early SAR efforts to modify compound 2 focused on exploring changes atthe P1′ position and N-terminal capping group. Recent SAR studies ofdiverse NS3/4A PIs indicate that replacement of thecyclopropylsulfonamide moiety at the P1′ position with a slightly morehydrophobic 1-methylcyclopropylsulfonamide improves inhibitor potency inreplicon assays. Moreover, changes at the P4 position have been shown toaffect inhibitor potency against drug resistant variants, as thesegroups bind in close proximity to the pivotal drug resistance siteAsp168. For carbamate-linked P4 capping groups, generally bulkyhydrophobic moieties are preferred but the size of the group appears tobe dependent on the heterocyclic moiety present at the P2 position.(Rudd, et al. ChemMedChem 2015, 10, 727-735; Vendeville, et al. Bioorg.Med. Chem. Lett. 2008, 18, 6189-6193; Moreau, et al. J Med. Chem. 2014,57, 1770-1776; O'Meara, et al. J Biol. Chem. 2013, 288, 5673-5681.)

First, replacing the cyclopropylsulfonamide at the P1′ position in 2with 1-methylcyclopropylsulfonamide provided the analogue 19a. Comparedto the parent compound 2, 19a showed slightly better Ki values againstWT, D168A and GT3a proteases and exhibited similar or slightly betterantiviral potency against WT and drug resistant variants.

Next, the tert-butyl P4 capping group in both 2 and 19a was replacedwith a larger cyclopentyl moiety, resulting in analogues 22a and 23a.Unlike the change at the P1′ position, the P4 cyclopentyl modificationprovided mixed results. Compound 22a afforded a 2-fold increase inpotency than 2 in biochemical assays against WT protease and a slightimprovement against the D168A variant, but was equipotent to 2 againstGT3a protease. Similarly, in replicon assays 22a exhibited 2-foldenhanced potency against WT HCV and D168A variant, but showed similarpotency as 2 against the R155K and D168V variants.

Compound 23a, with a 1-methylcyclopropylsulfonamide moiety at the P1′position and a cyclopentyl group at the P4 position, exhibited potencyprofile largely similar to 22a. Surprisingly, a slight loss in potencywas observed against the A156T variant for compounds with a cyclopentylversus tert-butyl capping group. Overall, these minor modifications atthe P1′ and N-terminal capping regions of inhibitor 2 were tolerated andprovided analogues with improved potency profiles.

SAR Exploration of P2 Quinoxaline

Next, SARs at the P2 quinoxaline in compound 2 were explored. Effortsmainly focused on replacing the 3-position ethyl group with diversefunctional groups with respect to size and electronic properties.Replacement of the ethyl group in 2 with a smaller methyl group providedanalogue 18b. As expected, reducing the size of the hydrophobic group atthis position resulted in improved potency profile. Compound 18b showedslightly enhanced potency against drug resistant variants in biochemicaland antiviral assays, with a notable ˜2-fold improvement against theD168V variant (EC₅₀=3.17 nM). The introduction of1-methylcyclopropylsulfonamide moiety at the P1′ position affordedinhibitor 19b with protease inhibitory activity comparable to the parentcompound 18b.

However, similar to the 3-ethylquinoxaline analogue (19a), compound 19bdemonstrated significant gain in potency in replicon assays. In fact,compared to 2, 19b exhibited 2- to 6-fold enhancement in potency againstdrug resistant variants R155K (EC₅₀=0.80 nM), A156T (EC₅₀=1.57 nM),D168A (EC₅₀=2.37 nM), and D168V (EC₅₀=1.6 nM). Replacement of thetert-butyl P4 capping in 18b and 19b with a cyclopentyl group, providing22b and 23b, resulted in an increase in WT and D168A inhibitory activityas well as 2- to 3-fold increase in WT replicon potency. Unlike thecorresponding 3-ethylquinoxaline analogues (22a and 23a), the3-methyquinoxaline compounds 22b and 23b maintained the excellentpotency profile observed for the corresponding tert-butyl analogues.Remarkably, with the exception of 18b (A156T EC₅₀=5.95 nM), allcompounds in the 3-methylquinoxaline series display exceptional potencyprofiles with EC₅₀ values below 5 nM against WT and clinically relevantdrug resistant variants.

To gain insights into the excellent potency profile observed for the3-methyquinoxaline series, the X-ray crystal structure of inhibitor 19bin complex with the WT NS3/4A protease was determined at a resolution of1.8 Å (FIG. 3 , Table 5, PDB code: 5VOJ). The WT-19b complex structurewas compared with the previously reported structures of compound 2 incomplex with WT protease and the A156T variant (PDB codes: 5EPN and5EPY). (Soumana, et al. ACS Chem. Biol. 2016, 11, 900-909.)

The two WT structures overlap very well, with only minor differences inthe S1 and S2 subsites because of modifications in the inhibitorstructure. In the WT-2 crystal structure, the 3-ethyl group at the P2quinoxaline makes hydrophobic interactions with the hydrocarbon portionof the Arg155 side-chain, while the methylene portion of this groupinteracts with the side-chain of Ala156. The smaller methyl group atthis position in the WT-19b structure maintains hydrophobic interactionswith Ala156, while minimizing chances of steric clash with a largerside-chain, such as in A156T.

Unlike inhibitor 1, the P1-P3 macrocyclic analogues retain potencyagainst the A156T variant. Comparison of the WT-2 and A156T-2 (PDB code:5EPY) structures shows subtle changes in inhibitor interactions with themutant protease. (Soumana, et al. ACS Chem. Biol. 2016, 11, 900-909.)

In the A156T-2 structure the P2 quinoxaline largely maintainsinteractions with the catalytic residues, but the ethyl group is shiftedaway from Arg155 side chain toward A156T. Moreover, to accommodate alarger Thr side-chain, the Asp168 side chain adopts anotherconformation, moving away from Arg155. These changes underlie reducedinhibitor potency against the A156T variant, but unlike 1, inhibitor 2is able to better accommodate these changes due to a flexible P2 moiety.The 3-methylquinoxaline analogues are more potent against the A156Tvariant than the corresponding 3-ethylquinoxaline compounds likely duethe reduced interactions of the smaller methyl group with the Thrside-chain. Replacing the methyl group with hydrogen at the 3-positionof quinoxaline would further reduce interactions with the S2 subsiteresidues, but was predicted to result in a highly flexible P2 moiety,likely destabilizing interactions with the catalytic residues. Thus, asmall hydrophobic group at the 3-position of P2 quinoxaline is preferredto maintain favorable interactions with Ala156 and avoid steric clasheswith the Thr side-chain in the A156T variant.

The improved potency profile of 3-methyquinoxaline compounds led toexploration of bioisosteric replacements of the 3-methyl group withvaried size and electronic properties. To that end, analogues 18c and19c bearing the 3-chloro-7-methoxyquinoxaline at the P2 position wereprepared. The protease inhibitory potency profiles of these compoundswere excellent and showed improvement against WT, D168A and GT3a over 2.These potency gains were not only maintained in replicon assays but weremore significant, with the only exception of A156T variant. Bothcompounds 18c and 19c were more active than the corresponding3-methylquinoxaline analogues (18b and 19b) with EC₅₀ values less than 1nM against WT, R155K and D168V and less than 2 nM against the D168Avariant, but experienced about 3- to 6-fold reduction in potency againstthe A156T variant. However, potency losses against the A156T variantwere largely reversed when the P4 tert-butyl group in 18c and 19c wasreplaced with a larger cyclopentyl moiety to afford 22c and 23c. Similarto the 3-methylquinoxaline compounds, the 3-chloroquinoxaline analoguesdisplayed exceptional potency profiles with EC₅₀ values of less than 5nM against all drug resistant variants including A156T. These resultsclearly demonstrate that small hydrophobic groups with weakelectron-donating properties at the 3-position of P2 quinoxaline can bereplaced with weak electron-withdrawing groups without affecting theoverall potency profile.

Next, a larger and strongly electron-withdrawing trifluoromethyl moietywas explored at the 3-position of P2 quinoxaline, leading to inhibitors18d and 19d. This modification, however, resulted in significant potencylosses in both biochemical and replicon assays. Compound 18d was about2- to 4-fold less active than 2 against WT protease and variants.Analogue 19d with the 1-methylcyclopropylsulfonamide moiety at the P1′position showed similar trends when compared to the corresponding 19a.In line with biochemical data, both 18d and 19d suffered 2- to 6-folddecrease in replicon potency against WT and drug resistant variants,though 19d maintained relatively good potency profile.

In contrast to the results in previous series, the introduction of thelarger cyclopentyl P4 capping group, as in 22d and 23d, was detrimentalto replicon potency, particularly against the A156T variant. Moreover,compounds in the 3-(trifluoromethyl)quinoxaline series were among theleast active against the GT3a protease in biochemical assays. Theseresults indicate that strong electron-withdrawing groups at the3-position of the P2 quinoxaline may be detrimental to potency. It isnoted that a recent SAR study indicates that PIs incorporating the3-(trifluoromethyl)quinoxaline can be optimized with modifications atthe 7-position of quinoxaline in combination with changes at the P1-P3macrocycle and P4 capping group. (Gillis, et al. In Abstract of Papers,2nd Generation HCV protease inhibitors: Part 2, optimization of P2*,250th ACS National Meeting & Exposition, Boston, Mass., United States,Aug. 16-20, 2015, pp MEDI-240.)

To isolate the effects of larger size versus electronic properties onpotency, inhibitors 18e and 19e with the larger isopropyl group at the3-position of the P2 quinoxaline were designed, synthesized andevaluated. These compounds showed WT protease inhibitory activitysimilar to the corresponding 3-ethylquinoxaline analogues (2 and 19a),but experienced 2- to 4-fold reduced activity against the D168A variant.A broader reduction in potency was observed for both 18e and 19e inreplicon assays against WT and drug resistant variants.

The cyclopentyl P4 group in analogues 22e and 23e slightly improvedbiochemical and replicon potency against WT and D168A variants, but waslargely unfavorable to replicon potency against R155K and A156Tvariants. This trend is broadly similar to the results observed with the3-(trifluoromethyl)quinoxaline series.

Without wishing to be bound by the theory, the results indicated thatboth electronic properties and size of the group at the 3-position of P2quinoxaline are important for maintaining potency against drug resistantvariants. Modeling indicated that compared to 2 the P2 quinoxalinemoiety in 18e has to shift away from the catalytic triad in order toaccommodate the larger isopropyl group thereby weakening criticalstacking interactions with His57 (FIG. 4 ).

Overall, SAR data from the 3-isopropyl- and3-(trifluoromethyl)-quinoxaline series supports that large substituentsat the 3-position of P2 quinoxaline have detrimental effect on inhibitorpotency against drug resistant variants.

These findings were further reinforced by the results obtained for the3-(thiophen-2-yl)quinoxaline analogues 18f and 22f. Based on molecularmodeling, the large thiophene moiety in these compounds was expected tomake extensive interactions with the residues Arg155 and Ala156 (FIG. 4), resulting in improved potency against WT protease. However, mutationsat these positions as well as at Asp168 would cause significant potencylosses, as these residues are crucial for efficient inhibitor binding.Compound 18f (a previously reported NS3/4A protease inhibitorincorrectly labeled as ABT-450, Rosenquist, et al. J Med. Chem. 2014,57, 1673-1693; WO 2008/002924) showed a 3-fold enhancement in WTbiochemical potency but was dramatically less active against the D168Avariant, losing over 1800-fold potency (FIG. 6 ). Similarly, in repliconassays analogue 18f showed considerably reduced potency against all drugresistant variants with losses ranging from 20- to 250-fold compared toWT (Table 3 and Table 4). The cyclopentyl P4 analogue 22f alsoexperienced large potency losses against the variants, albeit to alesser extent than 18f. Thus inhibitors with large groups at the3-position of P2 quinoxaline are highly susceptible to mutations atresidues Arg155, Ala156 and Asp168, leading to poor resistance profiles.

The X-ray crystal structure of inhibitor 18f in complex with WT NS3/4Aprotease was determined at a resolution of 1.8 Å, providing insightsinto the binding modes of P2 quinoxaline with a larger thiophenesubstituent at the 3-position (FIG. 5 , Table 5, PDB code: 5VP9).Comparison of the WT-18f and WT-2 crystal structures showed significantdifferences in the interactions of quinoxaline moieties with thecatalytic triad and S2 subsite residues. As predicted by modeling, thequinoxaline moiety in WT-18f structure is shifted toward the active siteto accommodate the larger thiophene substituent. The thiophene ringmakes extensive interactions with residues in the S2 subsite, includingcation-a interactions with Arg155, resulting in improved inhibitorypotency against the WT protease. As this Arg155 conformation isstabilized by electrostatic interactions with Asp168, mutations ateither residue would disrupt inhibitor binding by loss of directinteractions as well as indirect structural effects. In addition, theA156T mutation would result in steric clash with the thiophene ring, asreflected in the antiviral data for this variant. These biochemical andstructural findings are in line with previous studies that showinhibitors that are dependent on extensive interactions with the S2subsite residues for potency are highly susceptible to mutations atresidues Arg155, Ala156 and Asp168.

TABLE 3 Inhibitory activity against wild-type NS3/4A protease and drugresistant variants

Ki (nM) (Fold change) GT1a WT GT1a D168A GT3a Inhibitor R¹ R² R³ NS3/4AProtease NS3/4A Protease NS3/4A Protease 2 OMe Et H 3.29 ± 0.52 82.4 ±4.4 204 ± 19  (25) (62) 19a OMe Et Me 1.82 ± 0.38 55.2 ± 5.3 171 ± 23 (30) (94) 22a OMe Et H 1.24 ± 0.14 52.3 ± 3.2 211 ± 18  (42) (170) 23aOMe Et Me 1.37 ± 0.34 55.2 ± 5.3 186 ± 30  (40) (136) 18b OMe Me H 3.40± 0.47 50.9 ± 3.7 152 ± 18  (15) (45) 19b OMe Me Me 3.60 ± 0.44 52.0 ±2.4 119 ± 18  (14) (33) 22b OMe Me H 0.93 ± 0.15 31.9 ± 2.5 147 ± 20 (34) (158) 23b OMe Me Me 1.13 ± 0.22 36.3 ± 1.8 121 ± 16  (32) (107) 18cOMe Cl H 1.07 ± 0.17 39.8 ± 3.4 67.5 ± 8.0  (37) (63) 19c OMe Cl Me 1.11± 0.38 77.7 ± 6.1 53.6 ± 5.9  (70) (48) 22c OMe Cl H 0.49 ± 0.15 30.6 ±2.6 85.6 ± 11   (62) (175) 23c OMe Cl Me 0.44 ± 0.15 25.7 ± 1.8 61.0 ±12   (58) (139) 18d OMe CF₃ H 13.3 ± 3.9  157 ± 12 344 ± 141 (12) (26)19d OMe CF₃ Me 5.77 ± 1.78 118 ± 13 231 ± 74  (20) (40) 22d OMe CF₃ H7.55 ± 2.39 115 ± 12 757 ± 334 (15) (100) 23d OMe CF₃ Me 8.14 ± 2.37 110± 14 433 ± 206 (14) (53) 18e OMe i-Pr H 4.27 ± 1.34 239 ± 20 NT (56) 19eOMe i-Pr Me 0.58 ± 0.08 211 ± 19 NT (364) 22e OMe i-Pr H 1.44 ± 0.46 161± 11 NT (112) 23e OMe i-Pr Me 1.34 ± 0.48 156 ± 17 NT (116) 18f H2-thiophene H 1.03 ± 0.13 1823 ± 347 NT (1770) 22f H 2-thiophene H 1.59± 0.56 900 ± 81 NT (566) 18g H Et H 7.18 ± 1.02 190 ± 13 NT (26) 22g HEt H 1.99 ± 0.48  107 ± 7.0 NT (54) GZR (1) 0.21 ± 0.03 49.1 ± 1.6 30.3± 1.9  (234) (144)

TABLE 4 Antiviral activity against wild-type HCV and drug resistantvariants

Replicon EC₅₀ (nM) (Fold change) Inhibitor R¹ R² R³ WT R155K A156T D168AD168V 2 OMe Et H 0.33 1.75   9.65 6.31  9.10 (5) (29) (19) (28) 19a OMeEt Me 0.43 1.80   4.52 4.97  6.42 (4) (11) (12) (15) 22a OMe Et H 0.142.08 11.8 3.60 11.9  (15) (84) (26) (85) 23a OMe Et Me 0.16 2.07 10.63.45  7.08 (13) (66) (22) (44) 18b OMe Me H 0.39 1.17   5.95 4.24  3.17(3) (15) (11) (8) 19b OMe Me Me 0.30 0.80   1.57 2.37  1.60 (3) (5) (8)(5) 22b OMe Me H 0.11 0.89   2.88 2.63  4.32 (8) (26) (24) (39) 23b OMeMe Me 0.13 1.09   3.99 2.16  2.85 (8) (31) (17) (22) 18c OMe Cl H 0.160.44 16.2 1.42  0.73 (3) (101) (9) (5) 19c OMe Cl Me 0.18 0.40   8.861.07  0.49 (2) (49) (6) (3) 22c OMe Cl H 0.15 0.59   3.55 1.32  1.55 (4)(24) (9) (10) 23c OMe Cl Me 0.15 0.56   4.32 0.97  1.09 (4) (29) (6) (7)18d OMe CF₃ H 1.98 3.45 36.2 16.8   17.1  (2) (18) (8) (9) 19d OMe CF₃Me 1.52 2.30 20.5 8.64  8.31 (2) (13) (6) (5) 22d OMe CF₃ H 4.86 7.97117    15.1   24.0  (2) (24) (3) (5) 23d OMe CF₃ Me 4.04 6.90 75.9 8.4611.4  (2) (19) (2) (3) 18e OMe i-Pr H 1.43 5.02 25.7 15.3   23.7  (4)(18) (11) (17) 19e OMe i-Pr Me 1.86 4.14 21.2 11.9   18.1  (2) (11) (6)(10) 22e OMe i-Pr H 0.48 7.63 32.1 7.96 30.1  (16) (67) (17) (63) 23eOMe i-Pr Me 0.59 6.83 27.6 7.91 18.2  (12) (47) (13) (31) 18f H2-thiophene H 0.98 21.7 256    111      193     (22) (261) (113) (197)22f H 2-thiophene H 0.40 19.2 183    42.2   70.0  (48) (458) (106) (175)18g H Et H 0.46 1.81 10.6 8.55 14.0  (4) (23) (19) (30) 22g H Et H 0.244.28 24.6 7.50 19.3  (18) (103) (31) (80) GZR (1) 0.14 1.89 238    9.69 5.41 (14) (1700) (69) (39)

TABLE 5 X-ray data collection and crystallographic refinement statisticsWT1a-19b WT1a-18f PDB code: 5VOJ 5VP9 Resolution 1.80 Å 1.86 Å Spacegroup P2₁2₁2₁ P2₁2₁2₁ Molecules in AU^(a) 1 1 Cell dimensions a (Å) 55.454.8 b (Å) 58.6 58.4 c (Å) 59.9 60.4 β (°) 90 90 Completeness (%) 94.199.9 Total reflections 120670 111301 Unique reflections 17608 16852Average I/σ 7.8 15.7 Redundancy 6.9 6.6 R_(sym) (%)^(b) 5.0 (15.9) 6.0(31.7) RMSD^(c) in Bond lengths (Å) 0.005 0.005 Bond angles (°) 1.1 0.9R_(factor) (%)^(d) 16.0 16.8 R_(free) (%)^(e) 19.3 20.8 ^(a)AU,asymmetric unit. ^(b)R_(sym) = Σ | I − <I>|/Σ I, where I = observedintensity, <I> = average intensity over symmetry equivalent; values inparentheses are for the highest resolution shell. ^(c)RMSD, root meansquare deviation. ^(d)R_(factor) = Σ ∥ F_(o)| − |F_(c)∥/Σ|F_(o)|.^(e)R_(free) was calculated from 5% of reflections, chosen randomly,which were omitted from the refinement process.

As compounds 18f and 22f lacked the C-7 substituent at the P2quinoxaline, analogues 18g and 22g were prepared to investigate theeffect of this group on inhibitor potency. Compared to 2, analogue 18gexperienced about 2-fold decrease in biochemical potency and only minorloss in replicon potency against WT and drug resistant variants. The P4cyclopentyl analogue 22g resulted in about 2-fold reduced potencycompared to the corresponding compound 22a. Thus removal of the C-7methoxy group has minimal effect on inhibitor potency. Without wishingto be bound by the theory, the slightly reduced potency of 18g and 22gis likely due to the reduced hydrophobic interactions with the aromaticring of Tyr56 and the methylene portion of His57 of the catalytic triad.In contrast, the observed potency losses against resistant variants forthe 3-(thiophen-2-yl)quinoxaline compounds most likely result from lossof interactions of the 2-thiophene moiety with the S2 subsite residuesof the protease.

Effects of P2 Substituent Size and Flexibility

Taken together, the SAR results indicate that resistance profiles ofcompound 2 and analogues are strongly influenced by the substituent atthe 3-position of P2 quinoxaline and N-terminal capping group. While allPIs showed reduced potency against drug resistance variants in bothenzyme inhibition and replicon assays, fold potency losses variedsignificantly depending on the substituents at the 3-position of P2quinoxaline. To evaluate susceptibility to the clinically importantD168A variant, to which all current NS3/4A PIs are susceptible,potencies were normalized to WT for PIs with the same P4 capping groups(FIG. 6 ). Fold changes in Ki against the D168A protease variant for PIswith the same P1′ and P4 capping groups largely trended with the size ofthe substituent at the 3-position of P2 quinoxaline, with the exceptionof trifluoromethyl compounds. Losses in potency were significantlyhigher for compounds with the larger 2-thiophene substituent at the P2quinoxaline. These results strongly support using the substrate envelopemodel to reduce direct inhibitor interactions in the S2 subsite, therebyreducing inhibitor susceptibility to drug resistance.

The reduced potencies of NS3/4A PIs against drug resistant variantsR155K, A156T, and D168A/V mainly result from disruption of theelectrostatic interactions between Arg155 and Asp168. Compared to 1,compound 2 and most analogues incorporating flexible P2 quinoxalineshowed lower fold-changes in potency against these variants (Table 3 andTable 4).

In these P1-P3 macrocyclic PIs the conformational flexibility of the P2allows this moiety to adapt to the structural changes caused bymutations at Arg155, Ala156 and Asp168, resulting in better resistanceprofiles. Potency losses were higher for compound 1 because constraintimposed by the macrocycle does not allow the P2 moiety to adapt to thestructural changes resulting from these mutations. Compound 1 andsimilar P2-P4 macrocyclic PIs, such as voxilaprevir and glecaprevir, arelikely to be more susceptible to mutations that cause significantstructural changes in the protease active site. However, the P1-P3macrocyclic compounds disclosed herein are likely to be more effectiveagainst clinically relevant drug resistant variants. More broadly,combining the substrate envelope model with optimal conformationalflexibility provides a rational approach to design NS3/4A PIs withimproved resistance profiles.

Compound Syntheses

The NS3/4A PIs with diverse P2 quinoxaline moieties were synthesizedusing the reaction sequence outlined in Scheme 1.

Scheme 1. Synthesis of HCV NS3/4A Protease Inhibitors

-   -   Reagents and conditions: (a) Cs₂CO₃, NMP, 55° C., 6 h; (b) 4 N        HCl in dioxane, CH₂C₂, RT, 3 h; (c) HATU, DIEA, DMF, RT, 4        h; (d) LiOH.H₂O, THF, H₂O, RT, 24 h; (e) HATU, DIEA, DMF, RT, 2        h; (f) Zhan 1B catalyst, 1,2-DCE, 70° C., 6 h; (g) 4 N HCl,        dioxane, RT, 3 h; (h)N-(cyclopentyloxycarbonyloxy)-succinimide,        DIEA, CH₃CN, RT, 36 h.

A Cs₂CO₃-mediated S_(N)2 reaction of 3-substituted quinoxalin-2-ones6a-g with the activated proline derivative 8 provided the key P2intermediates 9a-g in 75-90% yield. The alternate S_(N)Ar reactionbetween activated quinoxaline derivatives and Boc-protectedhydroxy-proline resulted in lower yields, and purification of theresulting P2 acid products was significantly more challenging. The3-substituted 7-methoxy-quinoxalin-2-ones 6a-b and 6d-e were prepared bycondensation reactions of 4-methoxybenzene-1,2-diamine with thecorresponding ethyl glyoxylates. The 3-chloro-7-methoxyquinoxalin-2-one6c was prepared according to a reported method. (Harper, et al. ACS Med.Chem. Lett. 2012, 3, 332-336.)

The P1-P3 macrocyclic PIs were assembled from the P2 intermediates 9a-gusing a sequence of deprotection and peptide coupling steps followed bythe ring-closing metathesis (RCM) reaction (Method A). Removal of theBoc group in 9a-g using 4 N HCl provided the amine salts 10a-g, whichwere coupled with the amino acid 11 in the presence of HATU and DIEA toyield the P2-P3 ester intermediate 12a-g.

Hydrolysis of these esters with LiOH and reaction of the resultingcarboxylic acids 13a-g with the P1-P1′ fragments 14 and 15 underHATU/DIEA coupling conditions provided the bis-olefin intermediates16a-g and 17a-e. Cyclization of the bis-olefin intermediates wasaccomplished using a highly efficient RCM catalyst Zhan 1B, and providedthe inhibitors 18b-g and 19a-e in 45-80% yield.

Interestingly, RCM reactions of bis-olefins 17a-e bearing the1-methylcyclopropylsulfonamide provided higher yield than thecorresponding cyclopropylsulfonamide analogues 16a-g. Removal of the Bocgroup and reaction of the resulting amine salts 20a-g and 21a-e with theN-(cyclopentyloxycarbonyloxy)-succinimide in the presence of DIEAafforded the inhibitors 22a-g and 23a-e with the N-terminal cyclopentylP4 moiety.

Scheme 2. Alternate Synthesis of HCV NS3/4A Protease Inhibitors

-   -   Reagents and conditions: (a) HATU, DIEA, DMF, RT, 2 h; (b) Zhan        1B catalyst, 1,2-DCE, 70° C., 5 h; (c) LiOH.H₂O, THF, MeOH, H₂O,        RT, 24 h; (d) CDI, THF, DBU, reflux, 1.5 h, RT, 36 h.

A subset of inhibitors was synthesized using an alternate reactionsequence that allowed late-stage modification at both the P1′ and P4positions as illustrated in Scheme 2 (Method B). The P2-P3 acidintermediates 13a-d were reacted with the commercially available amine24 under HATU/DIEA coupling conditions to afford the bis-olefinintermediates 25a-d. RCM reaction in the presence of Zhan 1B catalystprovided the macrocyclic intermediates 26a-d in 75-90% yield, which wasbetter than that obtained in the presence of the P1′ acylsulfonamide.

The P1-P3 macrocyclic core intermediates 26a-d can be modified in eitherdirection after removing the C- or N-terminal protecting groups. Thus,hydrolysis of the C-terminal ethyl ester with LiOH provided the acids27a-d, which were then reacted with either cyclopropylsulfonamide 28 or1-methylcyclopropylsulfonamide 29 in the presence of CDI and DBU toafford the final inhibitors 18b-d and 19a-d. The N-terminal tert-butylcapping group was replaced with the cyclopentyl moiety as describedearlier to provide the target inhibitors 22a-d and 23a-d.

Experimental

All reactions were performed in oven-dried round bottomed or modifiedSchlenk flasks fitted with rubber septa under argon atmosphere, unlessotherwise noted. All reagents and solvents, including anhydroussolvents, were purchased from commercial sources and used as received.Flash column chromatography was performed using silica gel (230-400mesh, EMD Millipore). Thin-layer chromatography (TLC) was performedusing silica gel (60 F-254) coated aluminum plates (EMD Millipore), andspots were visualized by exposure to ultraviolet light (UV), exposure toiodine adsorbed on silica gel, and/or exposure to an acidic solution ofp-anisaldehyde (anisaldehyde) followed by brief heating. ¹H NMR and ¹³CNMR spectra were acquired on Varian Mercury 400 MHz and Bruker AvanceIII HD 500 MHz NMR instruments. Chemical shifts are reported in ppm (6scale) with the residual solvent signal used as reference and couplingconstant (J) values are reported in hertz (Hz). Data are presented asfollows: chemical shift, multiplicity (s=singlet, d=doublet, dd=doubletof doublet, t=triplet, q=quartet, m=multiplet, br s=broad singlet),coupling constant in Hz, and integration. High-resolution mass spectra(HRMS) were recorded on a Thermo Scientific Orbitrap Velos Pro massspectrometer coupled with a Thermo Scientific Accela 1250 UPLC and anautosampler using electrospray ionization (ESI) in the positive mode.The purity of final compounds was determined by analytical HPLC and wasfound to be >95% pure. HPLC was performed on a Waters Alliance 2690system equipped with a Waters 2996 photodiode array detector and anautosampler under the following conditions: column, Phenomenex Luna-2RP-C18 (5 μm, 4.6×250 mm, 120 Å, Torrance, Calif.); solvent A, H₂Ocontaining 0.1% formic acid (FA), solvent B, CH₃CN containing 0.1% FA;gradient, 50% B to 100% B over 15 min followed by 100% B over 5 min;injection volume, 10 μL; flow rate, 1 mL/min. Retention times and puritydata for each target compound are provided in the experimental section.

Typical Procedures for Synthesis of Protease IOnhibitors Using Method A1-(tert-Butyl) 2-methyl(2S,4R)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9a)

A solution of 3-ethyl-7-methoxyquinoxalin-2-one 6a (3.0 g, 14.7 mmol) inanhydrous NMP (45 mL) was treated with Cs₂CO₃ (7.40 g, 22.7 mmol). Afterstirring the reaction mixture at room temperature for 15 min, prolinederivative 8 (6.20 g, 13.3 mmol) was added in one portion. The reactionmixture was heated to 55° C., stirred for 4 h, and then another portionof proline derivative 8 (0.48 g, 1.0 mmol) was added. The resultingreaction mixture was stirred at 55° C. for additional 2 h, cooled toroom temperature, quenched with aqueous 1 N HCl solution (150 mL), andextracted with EtOAc (300 mL). The organic fraction was washedsuccessively with saturated aqueous NaHCO₃ and NaCl (150 mL each), dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash column chromatography using 15-30% EtOAc/hexanesas the eluent to provide 9a (5.50 g, 87%) as a white foamy solid. ¹H NMR(400 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.85 (d, J=9.0Hz, 1H), 7.18 (m, 1H), 7.11 (d, J=2.8 Hz, 1H), 5.73 (br s, 1H), 4.47 (t,J=8.0 Hz, 1H), 3.98-3.86 (m, 5H), 3.78 (s, 3H), 2.92 (q, J=7.2 Hz, 2H),2.68-2.60 (m, 1H), 2.43-2.36 (m, 1H), 1.43 (s, 9H), 1.31 (t, J=7.2 Hz,3H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.56, 160.59, 155.38, 154.02,148.95, 141.26, 134.12, 129.07, 119.02, 106.11, 80.76, 73.81, 58.43,55.93, 52.73, 52.40, 36.88, 28.47, 26.68, 11.97 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₂H₃₀N₃O₆, 432.2129; found 432.2135.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9d)

The same procedure was used as described above for compound 9a.7-methoxy-3-(trifluoromethyl)quinoxalin-2(1H)-one 8d (4.76 g, 19.5 mmol)in NMP (65 mL) was treated with Cs₂CO₃ (9.80 g, 30.0 mmol) and prolinederivative 3 (9.0 g, 19.3 mmol) to provide 9d (6.50 g, 71%) as a paleyellow foamy solid. ¹H NMR (500 MHz, CDCl₃) (mixture of rotamers, majorrotamer) δ 7.77 (d, J=9.0 Hz, 1H), 7.48-7.43 (m, 2H), 5.76 (br s, 1H),4.50 (t, J=8.0 Hz, 1H), 3.97-3.91 (m, 5H), 3.78 (s, 3H), 2.69-2.64 (m,1H), 2.41-2.34 (m, 1H), 1.42 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ173.43, 159.58, 153.98, 152.11, 138.39, 137.22, 127.99, 125.73, 120.70(q, J=273.4 Hz), 107.64, 80.69, 74.62, 58.27, 56.02, 52.32, 52.11,36.70, 28.34 ppm; ¹⁹F NMR (470 MHz, CDCl₃); -67.73 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₁H₂₅F₃N₃O₆, 472.1690; found 472.1689.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12a)

A solution of ester 9a (4.80 g, 11.1 mmol) in anhydrous CH₂Cl₂ (30 mL)was treated with a solution of 4 N HCl in 1,4-dioxane (30 mL). Afterstirring the reaction mixture at room temperature for 3 h, solvents wereevaporated under reduced pressure, and the residue was dried under highvacuum. The pale yellow solid was triturated with diethyl ether (3×30mL) and dried under high vacuum to yield the amine salt 10a (4.0 g, 98%)as an off-white powder.

A mixture of amine salt 10a (4.0 g, 10.9 mmol) and(S)-2-((tert-butoxycarbonyl)amino)non-8-enoic acid 11 (3.0 g, 11.1 mmol)in anhydrous DMF (60 mL) was treated with DIEA (7.30 mL, 44.2 mmol) andHATU (6.35 g, 16.7 mmol). The resulting reaction mixture was stirred atroom temperature for 4 h, then diluted with EtOAc (400 mL), and washedsuccessively with aqueous 0.5 N HCl, saturated aqueous NaHCO₃, andsaturated aqueous NaCl (250 mL each). The organic portion was dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash chromatography using 20-30% EtOAc/hexanes as theeluent to provide 12a (5.50 g, 86%) as a white foamy solid. ¹H NMR (400MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.86 (d, J=8.8 Hz,1H), 7.20 (dd, J=9.2, 2.8 Hz, 1H), 7.12 (d, J=2.8 Hz, 1H), 5.87-5.75 (m,2H), 5.20 (d, J=8.4 Hz, 1H), 5.02-4.92 (m, 2H), 4.73 (t, J=8.4 Hz, 1H),4.38 (q, J=7.2 Hz, 1H), 4.17 (d, J=12.0 Hz, 1H), 4.06 (dd, J=11.6, 4.4Hz, 1H), 3.94 (s, 3H), 3.78 (s, 3H), 2.90 (q, J=7.6 Hz, 2H), 2.69-2.64(m, 1H), 2.41-2.34 (m, 1H), 2.05 (app q, J=6.8 Hz, 2H), 1.82-1.74 (m,1H), 1.63-1.56 (m, 1H), 1.45-1.25 (m, 18H) ppm; ¹³C NMR (100 MHz, CDCl₃)δ 172.34, 171.96, 160.61, 155.61, 155.13, 148.95, 141.08, 139.18,129.22, 119.08, 114.58, 106.14, 79.84, 74.48, 58.19, 55.91, 52.88,52.67, 52.05, 35.16, 33.88, 32.88, 29.14, 28.96, 28.46, 26.52, 24.92,11.86 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₁H₄₅N₄O₇ 585.3283; found585.3286.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12d)

The same procedure was used as described above for compound 12a.Compound 9d (6.0 g, 12.7 mmol) was treated with 4 N HCl (40 mL) toafford amine salt 10d (5.10 g, 12.5 mmol), which was coupled with acid11 (3.80 g, 14.0 mmol) using DIEA (9.25 mL, 56.0 mmol) and HATU (7.60 g,20.0 mmol) to provide 12d (6.40 g, 81%) as a pale yellow foamy solid. ¹HNMR (500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.78 (d,J=9.0 Hz, 1H), 7.48 (dd, J=9.0, 2.5 Hz, 1H), 7.44 (d, J=2.5 Hz, 1H),5.86 (br s, 1H), 5.84-5.78 (m, 1H), 5.18 (d, J=9.0 Hz, 1H), 5.01-4.92(m, 2H), 4.75 (t, J=8.0 Hz, 1H), 4.35 (q, J=7.5 Hz, 1H), 4.19 (d, J=12.0Hz, 1H), 4.08 (dd, J=11.5, 4.5 Hz, 1H), 3.95 (s, 3H), 3.78 (s, 3H),2.70-2.65 (m, 1H), 2.41-2.35 (m, 1H), 2.04 (app q, J=7.0 Hz, 2H),1.80-1.75 (m, 1H), 1.60-1.54 (m, 1H), 1.45-1.28 (m, 15H) ppm; ¹³C NMR(125 MHz, CDCl₃) δ 172.10, 171.60, 159.99, 155.37, 151.78, 138.98,138.41, 136.93, 134.40 (q, J=36.3 Hz), 127.85, 125.66, 120.53 (q,J=273.4 Hz), 114.33, 107.54, 79.58, 75.05, 57.83, 55.91, 52.44, 52.33,51.75, 34.77, 33.65, 32.70, 28.91, 28.73, 28.18, 24.70 ppm; ¹⁹F NMR (470MHz, CDCl₃); -67.73 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₀H₄₀F₃N₄O₇,625.2844; found 625.2844.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(16a)

A solution of ester 12a (5.86 g, 10.0 mmol) in THF-H₂O mixture (1:1, 140mL) was treated with LiOH.H₂O (1.40 g, 33.4 mmol). The resultingreaction mixture was stirred at room temperature for 24 h. The reactionmixture was cooled to ˜5° C., acidified to a pH of 2.0 by slow additionof aqueous 0.25 N HCl (˜ 200 mL), and extracted with EtOAc (2×400 mL).The organic portions were washed separately with saturated aqueous NaCl(200 ml), dried (Na₂SO₄), filtered, and evaporated under reducedpressure. The gummy residue was dissolved in CHCl₃ (50 mL), concentratedunder reduced pressure, and the residue was dried under high vacuumovernight to yield the acid 13a (5.70 g, 100%) as a white foamy solid.

A mixture of acid 13a (2.10 g, 3.7 mmol) and amine salt 14 (1.20 g, 4.5mmol) in anhydrous DMF (35 mL) was treated with DIEA (2.43 mL, 14.7mmol) and HATU (2.1 g, 5.5 mmol). The resulting reaction mixture wasstirred at room temperature for 2.5 h, then diluted with EtOAc (300 mL)and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (200 mL each). The organic portionwas dried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash chromatography using 50-70% EtOAc/hexanesas the eluent to provide the bis-olefin compound 16a (2.50 g, 86%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.24 (s, 1H), 7.84 (d, J=8.8 Hz,1H), 7.18 (dd, J=8.8, 2.4 Hz, 1 H), 7.13 (d, J=2.8 Hz, 1H), 7.04 (s,1H), 5.91 (br s, 1H), 5.85-5.73 (m, 2H), 5.32 (d, J=8.4 Hz, 1H), 5.27(d, J=17.2 Hz, 1H), 5.14 (d, J=11.2 Hz, 1H), 5.01-4.90 (m, 2H), 4.47 (t,J=7.6 Hz, 1H), 4.38-4.33 (m, 1H), 4.20 (d, J=11.6 Hz, 1H), 4.02 (dd,J=11.2, 4.0 Hz, 1H), 3.94 (s, 3H), 2.96-2.84 (m, 3H), 2.56-2.51 (m, 2H),2.11 (q, J=8.8 Hz, 1H), 2.05-1.99 (m, 3H), 1.74-1.54 (m, 2H), 1.47-1.10(m, 21H), 1.08-1.03 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 174.09,172.58, 168.69, 160.54, 155.89, 154.99, 148.88, 140.95, 139.07, 134.69,132.71, 129.45, 119.02, 118.77, 114.67, 106.13, 80.0, 74.66, 60.61,55.91, 53.42, 52.62, 41.83, 35.46, 34.47, 33.89, 32.40, 31.39, 28.98,28.89, 28.47, 26.68, 25.47, 23.83, 11.85, 6.68, 6.26 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₃₉H₅₅N₆O₉S, 783.3746; found 783.3734.

tert-Butyl((S)-1-((2S,4R)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(17a)

The same procedure was used as described above for compound 16a. Acid13a (1.50 g, 2.6 mmol) was coupled with amine salt 15 (0.90 g, 3.2 mmol)using DIEA (1.75 mL, 10.6 mmol) and HATU (1.50 g, 3.9 mmol) to providethe bis-olefin compound 17a (1.75 g, 84%) as a white solid. ¹H NMR (400MHz, CDCl₃) δ 10.02 (s, 1H), 7.84 (d, J=9.2 Hz, 1H), 7.19 (dd, J=8.8,2.8 Hz, 1H), 7.13 (d, J=2.8 Hz, 1H), 7.06 (s, 1H), 5.90 (br s, 1H),5.83-5.73 (m, 2H), 5.37 (d, J=9.2 Hz, 1H), 5.27 (d, J=17.2 Hz, 1H), 5.14(d, J=10.8 Hz, 1H), 5.98 (dd, J=17.2, 1.6 Hz, 1H), 4.92 (dd, J=10.4, 1.2Hz, 1H), 4.48 (t, J=8.0 Hz, 1H), 4.39-4.33 (m, 1H), 4.16 (d, J=12.0 Hz,1H), 4.02 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H), 2.89 (q, J=7.6 Hz,2H), 2.57-2.50 (m, 2H), 2.12 (q, J=8.8 Hz, 1H), 2.05-1.99 (m, 3H),1.75-1.58 (m, 4H), 1.49 (s, 3H), 1.45-1.18 (m, 19H), 0.93-0.79 (m, 2H)ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.79, 172.41, 167.51, 160.31, 155.71,154.76, 148.63, 140.73, 138.85, 134.41, 132.60, 129.18, 118.80, 118.54,114.41, 105.89, 79.74, 74.42, 60.36, 55.68, 53.17, 52.43, 41.71, 36.56,35.23, 34.22, 33.64, 32.19, 28.70, 28.67, 28.25, 26.43, 25.35, 23.49,18.37, 14.27, 13.29, 11.64 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₄₀H₅₇N₆O₉S, 797.3902; found 797.3887.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(2)

A degassed solution of bis-olefin 16a (1.40 g, 1.8 mmol) in 1,2-DCE (300mL) was heated to 50° C. under argon, then Zhan 1b catalyst (0.150 g,0.20 mmol) was added in two portions over 10 min. The resulting reactionmixture was heated to 70° C. and stirred for 6 h. The reaction mixturewas cooled to room temperature and concentrated under reduced pressure.The residue was purified by flash chromatography using 50-80%EtOAc/hexanes as the eluent to yield the P1-P3 macrocyclic product 2(0.72 g, 53%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.28 (s,1H), 7.84 (d, J=9.6 Hz, 1H), 7.20-7.15 (m, 2H), 6.91 (s, 1H), 5.90 (brs, 1H), 5.69 (q, J=8.8 Hz, 1H), 5.14 (d, J=7.6 Hz, 1H), 4.96 (t, J=9.2Hz, 1H), 4.59 (t, J=7.6 Hz, 1H), 4.49 (d, J=11.6 Hz, 1H), 4.30-4.24 (m,1H), 4.02 (dd, J=10.8, 4.0 Hz, 1H), 3.94 (s, 3H), 2.94-2.85 (m, 3H),2.70-2.51 (m, 3H), 2.31 (q, J=8.8 Hz, 1H), 1.93-1.64 (m, 2H), 1.60-1.05(m, 24H), 0.95-0.89 (m, 1H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.15,173.28, 168.02, 160.29, 155.00, 154.90, 148.66, 140.88, 136.31, 134.28,128.90, 124.47, 118.82, 105.91, 79.84, 74.68, 59.45, 55.72, 53.08,51.92, 44.57, 34.65, 32.81, 31.01, 29.70, 28.14, 27.11, 27.16, 26.31,26.06, 22.16, 20.92, 11.56, 6.67, 6.12 ppm; HRMS (ESI) m/z: [M+H]⁺ calcdfor C₃₇H₅₁N₆O₉S, 755.3433; found 755.3410. Anal. HPLC: t_(R) 14.23 min,purity 97%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(19a)

The same procedure was used as described above for compound 2.Bis-olefin 17a (1.45 g, 1.8 mmol) was treated with Zhan 1b catalyst(0.150 g, 0.20 mmol) in 1,2-DCE (300 mL) to afford the P1-P3 macrocyclicproduct 19a (1.0 g, 71%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃)δ 10.16 (s, 1H), 7.82 (d, J=10.0 Hz, 1H), 7.18-7.15 (m, 2H), 6.94 (s,1H), 5.90 (br s, 1H), 5.69 (q, J=9.2 Hz, 1H), 5.16 (d, J=8.0 Hz, 1H),4.99 (t, J=9.2 Hz, 1H), 4.59 (t, J=8.0 Hz, 1H), 4.49 (d, J=11.6 Hz, 1H),4.30-4.25 (m, 1H), 4.04 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H), 2.87 (q,J=7.6 Hz, 2H), 2.70-2.51 (m, 3H), 2.33 (q, J=8.0 Hz, 1H), 1.92-1.68 (m,4H), 1.60-1.15 (m, 24H), 0.85-0.78 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃)δ 177.19, 173.24, 167.0, 160.23, 154.99, 154.88, 148.73, 140.84, 136.26,134.25, 129.03, 124.89, 118.72, 105.92, 79.84, 74.67, 59.48, 55.72,53.11, 51.92, 44.71, 36.43, 34.68, 32.80, 29.62, 28.14, 27.09, 26.38,26.12, 22.19, 20.93, 18.17, 14.51, 12.50, 11.54 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₃₈H₅₃N₆O₉S, 769.3589; found 769.3561. Anal. HPLC:t_(R) 15.01 min, purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22a)

Compound 2 (0.40 g, 0.53 mmol) was treated with a solution of 4 N HCl in1,4-dioxane (10 mL). The reaction mixture was stirred at roomtemperature for 3 h, then concentrated under reduced pressure, and theresidue was dried under high vacuum. The off-white solid was trituratedwith diethyl ether (3×10 mL) and dried under high vacuum to yield theamine salt 20a (0.37 g, 100%) as a white powder.

A solution of the above amine salt 20a (0.37 g, 0.53 mmol) in anhydrousCH₃CN (15 mL) was treated with DIEA (0.35 mL, 2.1 mmol) andN-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66 mmol). Thereaction mixture was stirred at room temperature for 36 h, thenconcentrated under reduced pressure and dried under high vacuum. Theresidue was purified by flash chromatography using 50-90% EtOAc/hexanesas the eluent to provide the target compound 22a (0.32 g, 79%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.29 (s, 1H), 7.83 (d, J=9.6 Hz,1H), 7.21-7.16 (m, 2H), 6.94 (s, 1H), 5.93 (br s, 1H), 5.70 (q, J=8.8Hz, 1H), 5.26 (d, J=8.0 Hz, 1H), 4.96 (t, J=8.4 Hz, 1H), 4.86-4.82 (m,1H), 4.60 (t, J=7.6 Hz, 1H), 4.45 (d, J=11.2 Hz, 1H), 4.34-4.28 (m, 1H),4.03 (dd, J=11.2, 4.0 Hz, 1H), 3.94 (s, 3H), 2.93-2.85 (m, 3H),2.70-2.48 (m, 3H), 2.30 (q, J=8.8 Hz, 1H), 1.93-1.23 (m, 23H), 1.15-1.06(m, 2H), 0.96-0.88 (m, 1H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.18,173.03, 168.04, 160.28, 155.65, 154.93, 148.78, 140.90, 136.27, 134.20,128.92, 124.46, 118.80, 105.92, 77.87, 74.55, 59.47, 55.72, 53.01,52.17, 44.54, 34.58, 32.72, 32.63, 32.59, 31.01, 29.70, 27.14, 27.05,26.40, 26.05, 23.56, 22.16, 20.90, 11.61, 6.67, 6.12 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₃₈H₅₁N₆O₉S, 767.3433; found 767.3408. Anal. HPLC:t_(R) 14.50 min, purity 98%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(23a)

The same procedure was used as described above for compound 22a.Compound 19a (0.40 g, 0.52 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 21a, which was treated with DIEA (0.35 mL,2.1 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66mmol) to provide the target compound 23a (0.30 g, 74%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.17 (s, 1H), 7.81 (d, J=9.6 Hz, 1H),7.21-7.16 (m, 2H), 6.93 (s, 1H), 5.92 (br s, 1H), 5.70 (q, J=9.2 Hz,1H), 5.26 (d, J=7.6 Hz, 1H), 4.99 (t, J=9.6 Hz, 1H), 4.86-4.81 (m, 1H),4.59 (t, J=7.6 Hz, 1H), 4.45 (d, J=11.2 Hz, 1H), 4.34-4.28 (m, 1H), 4.04(dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H), 2.87 (q, J=7.2 Hz, 2H),2.70-2.48 (m, 3H), 2.32 (q, J=8.8 Hz, 1H), 1.92-1.23 (m, 27H), 0.85-0.78(m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.21, 172.99, 166.98, 160.22,155.63, 154.90, 148.84, 140.85, 136.22, 134.36, 129.05, 124.88, 118.70,105.93, 77.86, 74.54, 59.51, 55.71, 53.05, 52.16, 44.70, 36.43, 34.61,32.72, 32.64, 32.58, 29.63, 27.13, 27.06, 26.47, 26.12, 23.56, 22.18,20.94, 18.17, 14.49, 12.50, 11.59 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₉H₅₃N₆O₉S, 781.3589; found 781.3561. Anal. HPLC: t_(R) 15.25 min,purity 99%.

Typical Procedures for Synthesis of Protease Inhibitors Using Method B1-(tert-Butyl) 2-methyl(2S,4R)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9d)

A solution of 7-methoxy-3-(trifluoromethyl)quinoxalin-2(1H)-one 6d (4.76g, 19.5 mmol) in anhydrous NMP (65 mL) was treated with Cs₂CO₃ (9.80 g,30.0 mmol). After stirring the reaction mixture at room temperature for15 min, proline derivative 8 (8.50 g, 18.3 mmol) was added in oneportion. The reaction mixture was heated to 55° C., stirred for 4 h, andthen another portion of proline derivative 8 (0.48 g, 1.0 mmol) wasadded. The resulting reaction mixture was stirred at 55° C. foradditional 2 h, cooled to room temperature, quenched with aqueous 1 NHCl solution (200 mL), and extracted with EtOAc (400 mL). The organicfraction was washed successively with saturated aqueous NaHCO₃ and NaCl(200 mL each), dried (Na₂SO₄), filtered, and evaporated under reducedpressure. The residue was purified by flash column chromatography using15-30% EtOAc/hexanes as the eluent to provide 9d (6.50 g, 71%) as a paleyellow foamy solid. ¹H NMR (500 MHz, CDCl₃) (mixture of rotamers, majorrotamer) δ 7.77 (d, J=9.0 Hz, 1H), 7.48-7.43 (m, 2H), 5.76 (br s, 1H),4.50 (t, J=8.0 Hz, 1H), 3.97-3.91 (m, 5H), 3.78 (s, 3H), 2.69-2.64 (m,1H), 2.41-2.34 (m, 1H), 1.42 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ173.43, 159.58, 153.98, 152.11, 138.39, 137.22, 127.99, 125.73, 120.70(q, J=273.4 Hz), 107.64, 80.69, 74.62, 58.27, 56.02, 52.32, 52.11,36.70, 28.34 ppm; ¹⁹F NMR (470 MHz, CDCl₃); -67.73 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₁H₂₅F₃N₃O₆, 472.1690; found 472.1689.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12d)

A solution of ester 9d (6.0 g, 12.7 mmol) in anhydrous CH₂Cl₂ (40 mL)was treated with a solution of 4 N HCl in 1,4-dioxane (40 mL). Afterstirring the reaction mixture at room temperature for 3 h, solvents wereevaporated under reduced pressure, and the residue was dried under highvacuum. The pale yellow solid was triturated with diethyl ether (3×30mL) and dried under high vacuum to yield the amine salt 10d (5.10 g,98%) as a pale yellow powder.

A mixture of amine salt 10d (5.10 g, 12.5 mmol) and(S)-2-((tert-butoxycarbonyl)amino)non-8-enoic acid 11 (3.80 g, 14.0mmol) in anhydrous DMF (65 mL) was treated with DIEA (9.25 mL, 56.0mmol) and HATU (7.60 g, 20.0 mmol). The resulting reaction mixture wasstirred at room temperature for 4 h, then diluted with EtOAc (500 mL),and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (300 mL each). The organic portionwas dried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash chromatography using 20-30% EtOAc/hexanesas the eluent to provide 12d (6.40 g, 81%) as a pale yellow foamy solid.¹H NMR (500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.78 (d,J=9.0 Hz, 1H), 7.48 (dd, J=9.0, 2.5 Hz, 1H), 7.44 (d, J=2.5 Hz, 1H),5.86 (br s, 1H), 5.84-5.78 (m, 1H), 5.18 (d, J=9.0 Hz, 1H), 5.01-4.92(m, 2H), 4.75 (t, J=8.0 Hz, 1H), 4.35 (q, J=7.5 Hz, 1H), 4.19 (d, J=12.0Hz, 1H), 4.08 (dd, J=11.5, 4.5 Hz, 1H), 3.95 (s, 3H), 3.78 (s, 3H),2.70-2.65 (m, 1H), 2.41-2.35 (m, 1H), 2.04 (app q, J=7.0 Hz, 2H),1.80-1.75 (m, 1H), 1.60-1.54 (m, 1H), 1.45-1.28 (m, 15H) ppm; ¹³C NMR(125 MHz, CDCl₃) δ 172.10, 171.60, 159.99, 155.37, 151.78, 138.98,138.41, 136.93, 134.40 (q, J=36.3 Hz), 127.85, 125.66, 120.53 (q,J=273.4 Hz), 114.33, 107.54, 79.58, 75.05, 57.83, 55.91, 52.44, 52.33,51.75, 34.77, 33.65, 32.70, 28.91, 28.73, 28.18, 24.70 ppm; 19F NMR (470MHz, CDCl₃); -67.73 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₀H₄₀F₃N₄O₇,625.2844; found 625.2844.

Ethyl(1R,2S)-1-((2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-2-carboxamido)-2-vinylcyclopropane-1-carboxylate(25d)

A solution of ester 12d (6.40 g, 10.25 mmol) in THF-H₂O (1:1 mixture,140 mL) was treated with LiOH.H₂O (1.38 g, 32.0 mmol). The resultingreaction mixture was stirred at room temperature for 24 h, then cooledto ˜5° C., acidified to a pH of 2.0 by slow addition of aqueous 0.25 NHCl (˜ 200 mL), and extracted with EtOAc (2×500 mL). The organicportions were washed separately with saturated aqueous NaCl (250 ml),dried (Na₂SO₄), filtered, and evaporated under reduced pressure. Thegummy residue was dissolved in CHCl₃ (50 mL), concentrated under reducedpressure, and the residue was dried under high vacuum to yield the acid13d (6.12 g, 98%) as a pale yellow foamy solid.

A solution of acid 13d (6.12 g, 10.0 mmol) and amine salt 24 (2.50 g,13.0 mmol) in anhydrous CH₂Cl₂ (100 mL) was treated with DIEA (9.10 mL,55.0 mmol), HATU (5.30 g, 14.0 mmol) and DMAP (0.60 g, 4.9 mmol). Theresulting reaction mixture was stirred at room temperature for 14 h,then diluted with EtOAc (500 mL), and washed successively with aqueous1.0 N HCl, saturated aqueous NaHCO₃, and saturated aqueous NaCl (250 mLeach). The organic portion was dried (Na₂SO₄), filtered, and evaporatedunder reduced pressure. The residue was purified by flash chromatographyusing 25-35% EtOAc/hexanes as the eluent to provide the bis-olefincompound 25d (6.54 g, 87%) as a pale yellow foamy solid. ¹H NMR (500MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.78 (d, J=9.2 Hz,1H), 7.53 (br s, 1H), 7.47 (dd, J=9.2, 2.8 Hz, 1H), 7.43 (d, J=2.4 Hz,1H), 5.88 (br s, 1H), 5.81-5.70 (m, 2H), 5.30 (dd, J=16.8, 0.8 Hz, 1H),5.14-5.10 (m, 2H), 5.01-4.89 (m, 2H), 4.79 (dd, J=14.0, 5.6 Hz, 1H),4.35-4.29 (m, 1H), 4.21-4.08 (m, 3H), 3.94 (s, 3H), 2.90-2.82 (m, 1H),2.48-2.38 (m, 1H), 2.16 (q, J=9.0 Hz, 1H), 2.04-1.98 (m, 2H), 1.86 (dd,J=8.0, 5.2 Hz, 1H), 1.66-1.52 (m, 2H), 1.46 (dd, J=9.6, 5.6 Hz, 1H),1.43-1.21 (m, 19H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 173.02, 171.00,169.87, 159.62, 155.52, 152.03, 138.92, 138.48, 137.16, 133.66, 128.02,125.73, 120.72 (q, J=273.6 Hz), 118.08, 114.52, 107.66, 79.98, 75.26,61.40, 58.41, 56.02, 52.58, 52.43, 40.14, 33.89, 33.77, 32.76, 32.62,28.97, 28.78, 28.31, 25.18, 23.11, 14.48 ppm; ¹⁹F NMR (470 MHz, CDCl₃);-67.77 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₇H49F3N5O₈, 748.3528;found 748.3514.

Ethyl(2R,6S,13aS,14aR,16aS,Z)-6-((tert-butoxycarbonyl)amino)-2-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,6,7,8,9,10,11,13a,14,15,16,16a-tetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecine-14a(5H)-carboxylate(26d)

A degassed solution of bis-olefin 25d (1.50 g, 2.0 mmol) in 1,2-DCE (300mL) was heated to 50° C. under argon, then Zhan 1b catalyst (0.150 g,0.20 mmol) was added in two portions over 10 min. The resulting mixturewas heated to 70° C. and stirred for 5 h. The reaction mixture wascooled to room temperature and concentrated under reduced pressure. Theresidue was purified by flash chromatography using 25-35% EtOAc/hexanesas the eluent to yield the P1-P3 macrocyclic product 26d (1.0 g, 70%) asan off-white foamy solid. ¹H NMR (400 MHz, CDCl₃) δ 7.77 (d, J=8.8 Hz,1H), 7.47 (dd, J=8.8, 2.8 Hz, 1H), 7.44 (d, J=2.4 Hz, 1H), 7.03 (br s,1H), 5.84-5.80 (m, 1H), 5.56-5.49 (m, 1H), 5.32-5.22 (m, 2H), 4.92 (q,J=4.4 Hz, 1H), 4.49 (t, J=7.6 Hz, 1H), 4.24-4.05 (m, 4H), 3.95 (s, 3H),3.05-2.99 (m, 1H), 2.41-2.35 (m, 1H), 2.24-2.14 (m, 3H), 1.93-1.86 (m,2H), 1.66-1.60 (m, 1H), 1.55 (dd, J=96, 5.2 Hz, 1H), 1.46-1.20 (m, 18H)ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.81, 171.95, 169.74, 159.69, 155.21,152.20, 138.56, 137.25, 134.50, 128.08, 125.91, 125.84, 120.80 (q, J=276Hz), 107.73, 80.04, 75.42, 61.50, 58.08, 56.13, 52.21, 51.39, 41.36,32.16, 31.77, 28.45, 28.10, 28.02, 26.37, 25.74, 23.70, 22.57, 14.72ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₅H₄₅F₃N₅O₈, 720.3215; found720.3203.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(18d)

A solution of ester 12d (1.0 g, 1.4 mmol) in THF-MeOH—H₂O (1:1:1mixture, 20 mL) was treated with LiOH.H₂O (0.18 g, 4.2 mmol). Theresulting reaction mixture was stirred at room temperature for 24 h,then cooled to ˜5° C., acidified to a pH of 2.0 by slow addition ofaqueous 0.25 N HCl, and extracted with EtOAc (2×150 mL). The organicportions were washed separately with saturated aqueous NaCl (100 ml),dried (Na₂SO₄), filtered, and evaporated under reduced pressure. Thegummy residue was dissolved in CHCl₃ (10 mL), concentrated under reducedpressure, and the residue was dried under high vacuum to yield the acid27d (0.95 g, 98%) as a pale yellow foamy solid.

A mixture of acid 27d (0.40 g, 0.58 mmol) and CDI (0.131 g, 0.81 mmol)in anhydrous THF (8 mL) was heated at reflux for 1.5 h. The solution wascooled to room temperature and slowly added to a solution ofcyclopropanesulfonamide 28 (0.10 g, 0.82 mmol) in anhydrous THF (4 mL)followed by DBU (0.12 mL, 0.81 mmol). The resulting reaction mixture wasstirred at room temperature for 24 h, then quenched with aqueous 0.5 NHCl to pH ˜2. Solvents were partially evaporated under reduced pressure,and the residue was extracted with EtOAc (2×100 mL). The combinedorganic portions were washed with saturated aqueous NaCl (100 mL), dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash chromatography using 40-70% EtOAc/hexanes as theeluent to afford the title compound 18d (0.28 g, 60%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.28 (s, 1H), 7.83 (d, J=9.2 Hz, 1H), 7.49(dd, J=8.8, 2.8 Hz, 1H), 7.42 (d, J=2.8 Hz, 1H), 6.87 (s, 1H), 5.92 (brs, 1H), 5.70 (q, J=8.8 Hz, 1H), 5.13 (d, J=7.6 Hz, 1H), 4.97 (t, J=8.4Hz, 1H), 4.62-4.56 (m, 2H), 4.23-4.17 (m, 1H), 4.01 (dd, J=11.6, 3.2 Hz,1H), 3.94 (s, 3H), 2.93-2.87 (m, 1H), 2.68-2.50 (m, 3H), 2.31 (q, J=8.8Hz, 1H), 1.95-1.54 (m, 2H), 1.53-1.02 (m, 21H), 0.96-0.88 (m, 1H) ppm;¹³C NMR (100 MHz, CDCl₃) δ 176.99, 173.31, 167.91, 159.45, 154.93,151.76, 138.27, 136.99, 136.32, 134.56 (q, J=36.2 Hz), 127.99, 125.57,124.53, 120.8 (q, J=274.0 Hz), 107.40, 79.76, 75.54, 59.44, 55.89,52.72, 51.86, 44.65, 34.61, 32.82, 31.02, 29.61, 28.02, 27.04, 25.99,22.21, 20.93, 6.67, 6.12 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₆H₄₆F₃N₆O₉S, 795.2994; found 795.2974. Anal. HPLC: t_(R) 14.59 min,purity 100%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(19d)

The same procedure was used as described above for compound 18d. Acid27d (0.43 g, 0.62 mmol) was treated with CDI (0.141 g, 0.87 mmol),1-methylcyclopropanesulfonamide 29 (0.118 g, 0.87 mmol) and DBU (0.13mL, 0.87 mmol) to afford the title compound 19d (0.34 g, 68%) as a whitesolid. ¹H NMR (400 MHz, CDCl₃) δ 10.15 (s, 1H), 7.83 (d, J=9.2 Hz, 1H),7.48 (dd, J=9.2, 2.8 Hz, 1H), 7.42 (d, J=2.8 Hz, 1H), 6.90 (s, 1H), 5.91(s, 1H), 5.70 (q, J=9.2 Hz, 1H), 5.14 (d, J=7.6 Hz, 1H), 5.00 (t, J=9.2Hz, 1H), 4.62-4.55 (m, 2H), 4.24-4.18 (m, 1H), 4.02 (dd, J=11.6, 3.6 Hz,1H), 3.94 (s, 3H), 2.71-2.51 (m, 3H), 2.33 (q, J=8.4 Hz, 1H), 1.93-1.75(m, 4H), 1.56-1.18 (m, 21H), 0.85-0.78 (m, 2H) ppm; ¹³C NMR (100 MHz,CDCl₃) δ 177.30, 173.46, 167.15, 159.68, 155.16, 152.01, 138.50, 137.23,136.50, 134.60 (q, J=36.0 Hz), 128.23, 125.79, 125.19, 120.83 (d,J=274.0 Hz), 107.65, 80.01, 75.79, 59.70, 56.12, 52.97, 52.08, 45.03,36.65, 34.86, 33.06, 29.81, 28.26, 27.31, 27.24, 26.32, 22.47, 21.21,18.42, 14.73, 12.77 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₇H₄₈F₃N₆O₉S,809.3150; found 809.3129. Anal. HPLC: t_(R) 15.23 min, purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22d)

Compound 18d (0.40 g, 0.52 mmol) was treated with a solution of 4 N HClin 1,4-dioxane (10 mL). The reaction mixture was stirred at roomtemperature for 3 h, concentrated under reduced pressure, and theresidue was dried under high vacuum. The pale yellow solid wastriturated with diethyl ether (3×10 mL) and dried under high vacuum toyield the amine salt 20d (0.37 g, 100%) as a white powder.

A solution of the above amine salt 20d (0.37 g, 0.52 mmol) in anhydrousCH₃CN (15 mL) was treated with DIEA (0.35 mL, 2.1 mmol) andN-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66 mmol). Thereaction mixture was stirred at room temperature for 24 h, thenconcentrated under reduced pressure and dried under high vacuum. Theresidue was purified by flash chromatography using 50-90% EtOAc/hexanesas the eluent to provide the target compound 22d (0.30 g, 74%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.27 (s, 1H), 7.82 (d, J=9.2 Hz,1H), 7.48 (dd, J=9.2, 2.8 Hz, 1H), 7.42 (d, J=2.8 Hz, 1H), 6.78 (s, 1H),5.95 (s, 1H), 5.70 (q, J=9.6 Hz, 1H), 5.23 (d, J=8.0 Hz, 1H), 4.98 (t,J=8.8 Hz, 1H), 4.74-4.69 (m, 1H), 4.60 (t, J=7.6, 1H), 4.54 (d, J=11.6,1H), 4.25-4.19 (m, 1H), 3.99 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H),2.94-2.88 (m, 1H), 2.68-2.50 (m, 3H), 2.31 (q, J=8.8 Hz, 1H), 1.94-1.24(m, 21H), 1.20-1.07 (m, 2H), 0.96-0.89 (m, 1H) ppm; ¹³C NMR (100 MHz,CDCl₃) δ 177.33, 173.29, 168.27, 159.68, 155.87, 152.08, 138.56, 137.24,136.47, 134.74 (q, J=36.0 Hz), 128.24, 125.75, 124.79, 120.87 (d,J=273.2 Hz), 107.62, 78.02, 75.70, 59.68, 56.11, 52.90, 52.35, 44.83,34.71, 32.92, 32.81, 32.64, 31.26, 29.87, 27.27, 26.24, 23.81, 23.75,22.49, 21.11, 6.89, 6.34 ppm; HRMS (ESI) m/z: [M+H]+ calcd forC₃₇H₄₆F₃N₆O₉S, 807.2994; found 807.2976. Anal. HPLC: t_(R) 14.98 min,purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(23d)

The same procedure was used as described above for compound 22d.Compound 19d (0.40 g, 0.52 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt 21d, which was treated with DIEA (0.35mL, 2.1 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g,0.66 mmol) to provide the target compound 23d (0.30 g, 74%) as a whitesolid. ¹H NMR (400 MHz, CDCl3) δ 10.18 (s, 1H), 7.83 (d, J=9.6 Hz, 1H),7.48 (dd, J=8.8, 2.8 Hz, 1H), 7.41 (d, J=2.8 Hz, 1H), 6.94 (s, 1H), 5.94(s, 1H), 5.70 (q, J=8.8 Hz, 1H), 5.28 (d, J=7.6 Hz, 1H), 5.00 (t, J=8.8Hz, 1H), 4.74-4.69 (m, 1H), 4.60 (t, J=7.6, 1H), 4.54 (d, J=12.0, 1H),4.25-4.19 (m, 1H), 4.00 (dd, J=11.6, 3.6 Hz, 1H), 3.94 (s, 3H),2.68-2.50 (m, 3H), 2.31 (q, J=8.4 Hz, 1H), 1.92-1.20 (m, 24H), 0.85-0.78(m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.33, 173.25, 167.13, 159.68,155.84, 152.08, 138.56, 137.24, 136.44, 134.75 (q, J=35.2 Hz), 128.25,125.74, 125.21, 120.86 (d, J=274.0 Hz), 107.62, 78.02, 75.71, 59.73,56.12, 52.89, 52.34, 45.03, 36.65, 34.73, 32.93, 32.82, 32.64, 29.83,27.26, 27.21, 26.29, 23.81, 23.75, 22.52, 21.23, 18.42, 14.73, 12.76ppm. HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₈H₄₈F₃N₆O₉S, 821.3150; found821.3133. Anal. HPLC: t_(R) 15.65 min, purity 97%.

Synthesis of Quinoxalines Scheme 3: Synthesis of Quinoxalines

-   -   Reagents and conditions: (a) AcOH, rt, overnight, 50° C., 2        h; (b) aq. H₂SO₄ (1.8 M), rt, 24 h; (c) MeOH, rt, 24 h; (d)        Et₃N, 150° C., 2 h; (e) SOCl₂, DMF, 110° C., 1.5 h.

3-Ethyl-7-methoxyquinoxalin-2(1H)-one (8a)

A mixture of 4-methoxy-1,2-diaminobenzene 4 (5.0 g, 36.2 mmol) and ethyl2-oxobutanoate 6a (5.70 g, 43.8 mmol) in AcOH (25 mL) was stirred atroom temperature overnight and then heated at 50° C. for 2 h. AcOH wasremoved under reduced pressure, and the reside was extracted with CH₂Cl₂(2×150 mL). The combined organic portions were washed with H₂O and 10%aqueous Na₂CO₃ solution, dried (Na₂SO₄), and evaporated under reducedpressure. The residue was triturated with hexanes and filtered. Thesolid was mixed with EtOAc (25 mL), stirred at room temperature for 30min, filtered, and dried under high vacuum to provide the3-ethyl-7-methoxyquinoxaline 8a (6.0 g, 81%) as a light purple solid. ¹HNMR (500 MHz, DMSO-d₆) δ 12.17 (s, 1H), 7.61 (d, J=8.5 Hz, 1H), 6.85(dd, J=9.0, 2.5 Hz, 1H), 6.73 (d, J=2.5 Hz, 1H), 3.80 (s, 3H), 2.74 (q,J=7.5 Hz, 3H), 1.19 (t, J=7.5 Hz, 3H) ppm; ¹³C NMR (125 MHz, DMSO-d₆) δ160.30, 159.35, 155.26, 133.63, 129.78, 127.01, 111.78, 98.26, 55.97,26.17, 10.08 ppm; MS (ESI) m/z: [M+H]⁺ calcd for C₁₁H₁₃N₂O₂, 205.24;found 205.90.

7-Methoxy-3-methylquinoxalin-2(1H)-one (8b)

4-Methoxy-1,2-diaminobenzene 4 (130 g, 0.94 mol) was added to an aqueoussolution of sulfuric acid (1.8 M, 1300 mL) and the mixture was treatedwith ethyl pyruvate 6b (132 g, 1.14 mol). The resulting reaction mixturewas stirred at room temperature for 24 h, then treated with an aqueoussolution of 3 N NaOH till pH 7. After stirring the mixture for 30 min,the solid precipitate was filtered, washed with water and dried. Thesolid product was mixed with EtOAc (1000 mL), heated to 60° C., andvigorously stirred for 1 h. The solid was filtered, washed with EtOAcand dried under high vacuum to provide the 3-methyl-7-methoxyquinoxaline8b (135 g, 75%) as a light purple solid. ¹H NMR (500 MHz, DMSO-d₆) δ12.18 (s, 1H), 7.59 (d, J=9.0 Hz, 1H), 6.86 (dd, J=9.0, 3.0 Hz, 1H),6.73 (d, J=2.5 Hz, 1H), 3.81 (s, 3H), 2.34 (s, 3H) ppm; ¹³C NMR (125MHz, DMSO-d₆) δ 160.30, 155.85, 155.62, 133.82, 129.58, 127.02, 111.82,98.29, 55.97, 20.63 ppm; MS (ESI) m/z: [M+H]⁺ calcd for C₁₀H₁₁N₂O₂,191.21; found 191.30.

3-Chloro-7-methoxyquinoxalin-2(1H)-one (8c)

The title compound was prepared according to the method described byHarper et al.¹ ¹H NMR (500 MHz, DMSO-d₆) δ 7.35 (d, J=8.5 Hz, 1H), 6.65(d, J=2.5 Hz, 1H), 6.62 (dd, J=8.5, 2.5 Hz, 1H), 3.77 (s, 3H), 3.71 (brs, 1H) ppm; ¹³C NMR (125 MHz, DMSO-d₆) δ 159.79, 159.30, 145.76, 145.62,128.88, 128.02, 110.57, 103.48, 55.56 ppm; MS (ESI) m/z: [M+H]⁺ calcdfor C₉H₈ClN₂O₂, 211.62; found 211.60.

7-Methoxy-3-(trifluoromethyl)quinoxalin-2(1H)-one (8d)

A solution of ethyl trifluoropyruvate 6d (20.4 g, 120 mmol) in MeOH (50mL) was slowly added to 4-methoxy-1,2-diaminobenzene 4 (15.0 g, 108mmol). The resulting reaction mixture was stirred at room temperaturefor 24 h. The solid precipitate was filtered, washed with cold MeOH anddried. The solid residue was mixed with MeOH (60 mL), stirred at 50° C.for 30 min, cooled to 5° C., filtered, and dried under high vacuum toprovide the 7-methoxy-3-(trifluoromethyl)quinoxalin-2(1H)-one 8d (12 g,47%) as a mustard solid. ¹H NMR (500 MHz, DMSO-d₆) δ 13.01 (s, 1H), 7.41(d, J=2.5 Hz, 1H), 7.37 (dd, J=9.0, 2.5 Hz, 1H), 7.32 (d, J=9.0 Hz, 1H),3.84 (s, 3H) ppm; ¹³C NMR (125 MHz, DMSO-d₆) δ 156.33, 151.77, 144.50(q, J=36.4 Hz), 131.04, 128.59, 124.08, 120.66 (d, J=274.4 Hz), 117.23,110.88, 56.26 ppm; ¹⁹F NMR (470 MHz, DMSO-d₆); -68.45 ppm; MS (ESI) m/z:[M+Na]⁺ calcd for C₁₀H₇F₃N₂O₂Na, 267.16; found 267.40.

3-Isopropyl-7-methoxyquinoxalin-2(1H)-one (8e)

A mixture of 4-methoxy-1,2-diaminobenzene 4 (130 g, 0.94 mol) and ethyl3-methyl-2-oxobutanoate 6e (162 g, 1.12 mol) in AcOH (650 mL) wasstirred at room temperature overnight, and then heated at 50° C. for 2h. AcOH was removed under reduced pressure. The residue was diluted withH₂O (650 mL) and CH₂Cl₂ (800 mL) and the pH of the mixture was adjustedto pH ˜ 10 by slow addition of 10% aqueous NaOH solution. The resultingprecipitate was filtered, washed with CH₂Cl₂ (100 mL) and dried undervacuum to provide the 3-isopropyl-7-methoxyquinoxaline 8e (91 g, 45%) asa light brown solid. ¹H NMR (500 MHz, DMSO-d₆) δ 12.22 (s, 1H), 7.62 (d,J=9.0 Hz, 1H), 6.86 (dd, J=9.0, 3.0 Hz, 1H), 6.75 (d, J=2.5 Hz, 1H),3.81 (s, 3H), 3.43-3.37 (m, 1H), 1.19 (d, J=7.0 Hz, 6H) ppm; ¹³C NMR(125 MHz, DMSO-d₆) δ 162.35, 160.36, 154.91, 133.64, 129.90, 126.91,111.80, 98.24, 55.97, 30.08, 20.57 ppm; MS (ESI) m/z: [M+H]⁺ calcd forC₁₂H₁₅N₂O₂, 219.26; found 219.50.

3-(Thiophen-2-yl)quinoxalin-2(1H)-one (8f)

A mixture of 1,2-diaminobenzene 5 (5.41 g, 50 mmol) and ethyl2-oxo-2-(thiophen-2-yl)acetate 6f (9.2 g, 50 mmol) was stirred inethanol (100 ml) at reflux for 18 h. The reaction mixture was cooled to10° C. and stirred for 1 h. The solid precipitate was filtered, washedwith ethanol (20 mL) and dried under high vacuum to give the titlecompound 8f (6.0 g, 53%) as a yellow solid. ¹H NMR (500 MHz, DMSO-d₆) δ12.69 (s, 1H), 8.41 (dd, J=4.0, 1.5 Hz, 1H), 7.83 (dd, J=5.0, 1.0 Hz,1H), 7.77 (d, J=8.0 Hz, 1H), 7.51 (dt, J=8.0, 1.5 Hz, 1H), 7.35-7.30 (m,2H), 7.23 (dd, J=5.0, 3.5 Hz, 1H) ppm; ¹³C NMR (125 MHz, DMSO-d₆) δ153.42, 148.88, 138.92, 132.07, 131.89, 131.41, 131.36, 129.78, 128.11,128.0, 123.65, 115.28 ppm; MS (ESI) m/z: [M+H]⁺ calcd for C₁₂H₉N₂OS,229.28; found 229.50.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9b)

A solution of 3-ethyl-7-methoxyquinoxalin-2-one 8b (4.0 g, 21 mmol) inanhydrous NMP (65 mL) was treated with Cs₂CO₃ (10.30 g, 31.6 mmol).After stirring the reaction mixture at room temperature for 15 min,proline derivative 3 (8.82 g, 19.0 mmol) was added in one portion. Thereaction mixture was heated to 55° C., stirred for 4 h, and then anotherportion of proline derivative 3 (0.68 g, 1.5 mmol) was added. Theresulting reaction mixture was stirred at 55° C. for additional 2 h,cooled to room temperature, quenched with aqueous 1 N HCl solution (250mL), and extracted with EtOAc (400 mL). The organic fraction was washedsuccessively with saturated aqueous NaHCO₃ and NaCl (250 mL each), dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash column chromatography using 15-30% EtOAc/hexanesas the eluent to provide 9b (6.60 g, 75%) as a colorless gummy solid. ¹HNMR (500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.80 (d,J=9.0 Hz, 1H), 7.17 (dd, J=9.0, 3.0 Hz, 1H), 7.11 (d, J=2.5 Hz, 1H),5.71 (br s, 1H), 4.48 (t, J=8.0 Hz, 1H), 3.99-3.91 (m, 4H), 3.87 (d,J=12.5 Hz, 1H), 3.78 (s, 3H), 2.67-2.58 (m, 1H), 2.56 (s, 3H), 2.43-2.37(m, 1H), 1.43 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 173.36, 160.24,155.51, 153.81, 144.60, 141.04, 134.22, 128.95, 118.63, 105.95, 80.54,73.59, 58.20, 55.68, 52.48, 52.20, 36.70, 28.26, 19.93 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₂₁H₂₈N₃O₆, 418.1973; found 418.1976.

1-(tert-butyl) 2-methyl(2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9c)

The same procedure was used as described above for compound 9b.3-Chloro-7-methoxyquinoxalin-2(1H)-one 8c (4.0 g, 19.0 mmol) in NMP (60mL) was treated with Cs₂CO₃ (9.30 g, 28.6 mmol) and proline derivative 3(8.40 g, 18.1 mmol) to provide 9c (6.30 g, 76%) as an off-white foamysolid. ¹H NMR (400 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ7.80 (d, J=8.8 Hz, 1H), 7.21 (dd, J=8.8, 2.8 Hz, 1H), 7.12 (d, J=2.8 Hz,1H), 5.69 (br s, 1H), 4.52 (t, J=7.6 Hz, 1H), 4.0-3.94 (s, 4H), 3.88 (d,J=12.8 Hz, 1H), 3.78 (s, 3H), 2.72-2.62 (m, 1H), 2.45-2.37 (m, 1H), 1.43(s, 9H) ppm; ¹³C NMR (400 MHz, CDCl₃) δ 173.32, 162.35, 153.84, 152.48,141.03, 136.11, 134.06, 129.97, 119.95, 105.83, 80.60, 75.02, 58.10,55.81, 52.36, 52.10, 36.64, 28.27 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₂₀H₂₅ClN₃O₆, 438.1426; found 438.1438.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9e)

The same procedure was used as described above for compound 9b.3-Isopropyl-7-methoxyquinoxalin-2(1H)-one 8e (4.0 g, 18.3 mmol) in NMP(65 mL) was treated with Cs₂CO₃ (9.0 g, 27.6 mmol) and prolinederivative 3 (8.30 g, 17.9 mmol) to provide 9e (7.30 g, 90%) as acolorless gummy solid. ¹H NMR (500 MHz, CDCl₃) (mixture of rotamers,major rotamer) δ 7.83 (d, J=8.0 Hz, 1H), 7.16 (d, J=8.4 Hz, 1H), 7.10(s, 1H) 5.74 (br s, 1H), 4.48 (t, J=7.5 Hz, 1H), 3.92-3.87 (m, 5H), 3.78(s, 3H), 3.41-3.36 (m, 1H), 2.68-2.59 (m, 1H), 2.42-2.35 (m, 1H), 1.43(s, 9H), 1.31 (t, J=7.0 Hz, 6H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 173.37,160.19, 154.62, 153.82, 152.00, 140.68, 134.31, 129.39, 118.41, 105.80,80.49, 73.36, 58.28, 55.67, 52.58, 52.19, 36.68, 30.81, 28.25, 20.43,20.38 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₃H₃₂N₃O₆, 446.2286; found446.2287.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((3-(thiophen-2-yl)quinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9f)

The same procedure was used as described above for compound 9b.3-(Thiophen-2-yl)quinoxalin-2(1H)-one 8f (3.0 g, 13.1 mmol) in NMP (40mL) was treated with Cs₂CO₃ (6.62 g, 20.3 mmol) and proline derivative 3(6.0 g, 12.9 mmol) to provide 9f (4.90 g, 82%) as an off-white foamysolid. ¹H NMR (400 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ8.13 (t, J=4.0 Hz, 1H), 8.01 (d, J=7.6 Hz, 1H), 7.79 (t, J=8.0 Hz, 1H),7.66-7.55 (m, 2H), 7.53 (dd, J=5.2, 1.2 Hz, 1H), 7.20-7.14 (m, 1H), 5.91(br s, 1H), 4.56 (t, J=8.0 Hz, 1H), 4.08 (d, J=12.8 Hz, 1H), 4.0-3.95(m, 1H), 3.79 (s, 3H), 2.81-2.72 (m, 1H), 2.49-2.41 (m, 1H), 1.44 (s,9H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.30, 153.80, 152.45, 140.48,139.83, 138.93, 138.81, 130.35, 130.20, 129.45, 128.56, 128.09, 127.33,126.72, 80.56, 74.51, 58.27, 52.66, 52.26, 36.69, 28.27 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₂₃H₂₆N₃O₅S, 456.1588; found 456.1589.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((3-ethylquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(9g)

The same procedure was used as described above for compound 9b.Commercially available 3-ethyl-quinoxalin-2(1H)-one 8g (3.0 g, 17.2mmol) in NMP (40 mL) was treated with Cs₂CO₃ (8.42 g, 25.8 mmol) andproline derivative 3 (7.80 g, 16.8 mmol) to provide 9g (4.50 g, 65%) asa colorless gummy solid. ¹H NMR (400 MHz, CDCl₃) (mixture of rotamers,major rotamer) δ 7.95 (d, J=7.5 Hz, 1H), 7.76 (d, J=8.0 Hz, 1H),7.62-7.52 (m, 2H), 5.76 (br s, 1H), 4.47 (t, J=8.0 Hz, 1H), 3.95-3.88(m, 2H), 3.78 (s, 3H), 2.95 (q, J=7.6 Hz, 2H), 2.67-2.60 (m, 1H),2.42-2.37 (m, 1H), 1.43 (m, 9H), 1.33 (t, J=7.6 Hz, 3H) ppm; ¹³C NMR(100 MHz, CDCl₃) δ 173.31, 154.69, 153.80, 152.08, 139.40, 138.79,128.97, 128.28, 126.87, 126.69, 80.51, 73.63, 58.25, 52.52, 52.19,36.69, 28.25, 26.91, 11.50 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₂₁H₂₈N₃O₅, 402.2023; found 402.2026.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12b)

A solution of ester 9b (3.50 g, 8.4 mmol) in anhydrous CH₂Cl₂ (25 mL)was treated with a solution of 4 N HCl in 1,4-dioxane (25 mL). Afterstirring the reaction mixture at room temperature for 3 h, solvents wereevaporated under reduced pressure, and the residue was dried under highvacuum. The pale yellow solid was triturated with diethyl ether (3×25mL) and dried under high vacuum to yield the amine salt 10b (3.0 g,100%) as an off-white powder. A mixture of amine salt 10b (3.0 g, 8.4mmol) and (S)-2-((tert-butoxycarbonyl)amino)non-8-enoic acid 11 (2.50 g,9.2 mmol) in anhydrous DMF (45 mL) was treated with DIEA (6.10 mL, 36.8mmol) and HATU (5.25 g, 13.8 mmol). The resulting reaction mixture wasstirred at room temperature for 4 h, then diluted with EtOAc (400 mL),and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (250 mL each). The organic portionwas dried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash chromatography using 20-30% EtOAc/hexanesas the eluent to provide 12b (4.0 g, 83%) as a white foamy solid. ¹H NMR(500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.81 (d, J=9.0Hz, 1H), 7.18 (dd, J=9.0, 2.5 Hz, 1H), 7.12 (d, J=2.5 Hz, 1H), 5.84-5.75(m, 2H), 5.21 (d, J=8.5 Hz, 1H), 5.01-4.92 (m, 2H), 4.75 (t, J=8.0 Hz,1H), 4.38 (q, J=7.5 Hz, 1H), 4.18 (d, J=11.5 Hz, 1H), 4.06 (dd, J=12.0,4.5 Hz, 1H), 3.94 (s, 3H), 3.77 (s, 3H), 2.69-2.64 (m, 1H), 2.54 (s, 3H), 2.41-2.35 (m, 1H), 2.04 (app q, J=7.0 Hz, 2H), 1.80-1.75 (m, 1H),1.63-1.55 (m, 1H), 1.46-1.24 (m, 15H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ172.13, 171.78, 160.27, 155.40, 155.27, 144.62, 140.89, 138.96, 134.39,129.03, 118.73, 114.35, 105.99, 79.61, 74.30, 57.97, 55.66, 52.67,52.43, 51.83, 34.94, 33.65, 32.66, 28.91, 28.74, 28.25, 24.68, 19.87ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₀H₄₃N₄O₇, 571.3126; found571.3128.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12c)

The same procedure was used as described above for compound 12b.Compound 9c (3.25 g, 7.4 mmol) was treated with 4 N HCl (20 mL) toafford amine salt 10c (2.77 g, 7.4 mmol), which was coupled with acid 11(2.0 g, 7.4 mmol) using DIEA (4.90 mL, 29.6 mmol) and HATU (4.20 g, 11.0mmol) to provide 12c (3.30 g, 75%) as a white foamy solid. ¹H NMR (400MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.82 (d, J=9.2 Hz,1H), 7.23 (dd, J=9.2, 2.8 Hz, 1H), 7.15 (d, J=2.8 Hz, 1H), 5.85-5.75 (m,2H), 5.21 (d, J=8.4 Hz, 1H), 5.02-4.91 (m, 2H), 4.79 (t, J=8.4 Hz, 1H),4.37 (q, J=8.0 Hz, 1H), 4.24 (d, J=11.6 Hz, 1H), 4.07 (dd, J=11.6, 4.4Hz, 1H), 3.95 (s, 3H), 3.78 (s, 3H), 2.74-2.68 (m, 1H), 2.42-2.36 (m,1H), 2.04 (app q, J=6.8 Hz, 2H), 1.82-1.76 (m, 1H), 1.63-1.55 (m, 1H),1.43-1.27 (m, 15H) ppm; ¹³C NMR (400 MHz, CDCl₃) δ 172.33, 171.87,161.52, 155.59, 152.46, 141.06, 139.19, 136.28, 134.36, 129.17, 120.25,114.58, 106.03, 79.88, 75.92, 58.16, 56.02, 52.70, 52.58, 52.00, 34.99,33.88, 32.90, 29.14, 28.96, 28.46, 24.89 ppm; HRMS (ESI) m/z: [M+H]⁺calcd for C₂₉H₄₀ClN₄O₇, 591.2580; found 591.2582.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12e)

The same procedure was used as described above for compound 12b.Compound 9e (3.25 g, 7.3 mmol) was treated with 4 N HCl (25 mL) toafford amine salt 10e (2.80 g, 7.3 mmol), which was coupled with acid 11(2.20 g, 8.1 mmol) using DIEA (5.36 mL, 32.4 mmol) and HATU (4.64 g,12.2 mmol) to provide 12e (4.10 g, 93%) as a white foamy solid. ¹H NMR(500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.84 (d, J=8.5Hz, 1H), 7.18 (d, J=9.0 Hz, 1H), 7.11 (s, 1H), 5.87 (br s, 1H),5.84-5.76 (m, 1H), 5.20 (d, J=8.5 Hz, 1H), 4.99 (d, J=17.5 Hz, 1H), 4.93(d, J=10.0 Hz, 1H), 4.72 (t, J=8.0 Hz, 1H), 4.39 (q, J=7.0 Hz, 1H), 4.15(d, J=12.0 Hz, 1H), 4.06 (dd, J=12.0, 4.0 Hz, 1H) 3.94 (s, 3H), 3.78 (s,3H), 3.40-3.34 (m, 1H), 2.69-2.64 (m, 1H), 2.40-2.34 (m, 1H), 2.04 (appq, J=6.5 Hz, 2H), 1.82-1.75 (m, 1H), 1.63-1.56 (m, 1H), 1.45-1.20 (m,21H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 172.13, 171.69, 160.24, 155.38,154.36, 152.00, 140.52, 138.96, 134.50, 129.46, 118.53, 114.35, 105.82,79.59, 74.03, 58.01, 55.66, 52.71, 52.43, 51.85, 34.95, 33.66, 32.68,30.59, 28.92, 28.75, 28.23, 24.69, 20.55, 20.43 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₃₂H₄₇N₄O₇, 599.3439; found 599.3440.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((3-(thiophen-2-yl)quinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12f)

The same procedure was used as described above for compound 12b.Compound 9f (3.0 g, 6.6 mmol) was treated with 4 N HCl (20 mL) to affordamine salt 10f (2.60 g, 6.6 mmol), which was coupled with acid 11 (1.80g, 6.6 mmol) using DIEA (4.35 mL, 26.3 mmol) and HATU (3.75 g, 9.9 mmol)to provide 12f (3.0 g, 75%) as an off-white foamy solid. ¹H NMR (500MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 8.09 (dd, J=4.0, 1.2Hz, 1H), 8.02 (dd, J=8.0, 1.6 Hz, 1H), 7.79 (dd, J=8.8, 1.6 Hz, 1H),7.65-7.56 (m, 2H), 7.53 (dd, J=4.8, 0.8 Hz, 1H), 7.17 (dd, J=5.2, 4.0Hz, 1H), 6.03 (br s, 1H), 5.85-5.77 (m, 1H), 5.19 (d, J=8.4 Hz, 1H),5.03-4.92 (m, 2H), 4.83 (t, J=8.0 Hz, 1H), 4.43 (q, J=7.2 Hz, 1H), 4.32(d, J=12.0 Hz, 1H), 4.12 (dd, J=12.0, 4.4 Hz, 1H), 3.79 (s, 3H),2.83-2.77 (m, 1H), 2.48-2.41 (m, 1H), 2.05 (app q, J=6.8, 2H), 1.83-1.77(m, 1H), 1.65-1.57 (m, 1H), 1.46-1.20 (m, 15H) ppm; ¹³C NMR (125 MHz,CDCl₃) δ 172.11, 171.64, 155.38, 152.25, 140.51, 139.45, 138.97, 138.76,130.46, 130.34, 129.46, 128.60, 128.19, 127.45, 126.71, 114.36, 79.59,75.08, 58.01, 52.72, 52.46, 51.92, 34.91, 33.66, 32.62, 28.92, 28.75,28.22, 24.76 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₂H₄₁N₄O₆S,609.2741; found 609.2739.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((3-ethylquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(12g)

The same procedure was used as described above for compound 12b.Compound 9g (3.50 g, 8.4 mmol) was treated with 4 N HCl (25 mL) toafford amine salt 10g (3.0 g, 17.2 mmol), which was coupled with acid 11(2.50 g, 9.2 mmol) using DIEA (6.10 mL, 36.8 mmol) and HATU (5.25 g,13.8 mmol) to provide 12g (4.0 g, 83%) as a white foamy solid. ¹H NMR(400 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.97 (dd, J=8.0,1.6 Hz, 1H), 7.77 (d, J=8.0, 1.6 Hz, 1H), 7.63-7.53 (m, 2H), 5.88 (br s,1H), 8.84-5.75 (m, 1H), 5.21 (d, J=9.2 Hz, 1H), 5.02-4.91 (m, 2H), 4.74(t, J=8.4 Hz, 1H), 4.37 (q, J=8.0 Hz, 1H), 4.18 (d, J=11.6 Hz, 1H), 4.07(dd, J=11.6, 4.4 Hz, 1H), 3.78 (s, 3H), 2.93 (q, J=7.6 Hz, 2H),2.71-2.63 (m, 1H), 2.42-2.35 (m, 1H), 2.05 (app q, J=6.8 Hz, 2H),1.82-1.74 (m, 1H), 1.62-1.55 (m, 1H), 1.45-1.29 (m, 18H) ppm; ¹³C NMR(100 MHz, CDCl₃) δ 172.05, 171.85, 155.39, 154.42, 152.0, 139.20,138.94, 138.84, 129.02, 128.27, 126.81, 114.34, 79.55, 74.23, 57.93,52.62, 52.44, 51.81, 34.85, 33.64, 32.57, 28.87, 28.70, 28.20, 26.69,24.70, 11.40 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₀H₄₃N₄O₆, 555.3177;found 555.3177.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(16b)

A solution of ester 12b (3.25 g, 5.7 mmol) in THF-H₂O mixture (1:1, 100mL) was treated with LiOH.H₂O (0.72 g, 17.2 mmol). The resultingreaction mixture was stirred at room temperature for 24 h. The reactionmixture was cooled to ˜5° C., acidified to a pH of 2.0 by slow additionof aqueous 0.25 N HCl (˜200 mL), and extracted with EtOAc (2×400 mL).The organic portions were washed separately with saturated aqueous NaCl(200 ml), dried (Na₂SO₄), filtered, and evaporated under reducedpressure. The gummy residue was dissolved in CHCl₃ (50 mL), concentratedunder reduced pressure, and the residue was dried under high vacuumovernight to yield the acid 13b (3.17 g, 100%) as a white foamy solid.

A mixture of acid 13b (1.60 g, 2.9 mmol) and amine salt 14 (0.93 g, 3.5mmol) in anhydrous DMF (35 mL) was treated with DIEA (2.0 mL, 11.5 mmol)and HATU (1.75 g, 4.6 mmol). The resulting reaction mixture was stirredat room temperature for 2.5 h, then diluted with EtOAc (250 mL) andwashed successively with aqueous 0.5 N HCl, saturated aqueous NaHCO₃,and saturated aqueous NaCl (150 mL each). The organic portion was dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash chromatography using 50-70% EtOAc/hexanes as theeluent to provide the bis-olefin compound 16b (1.57 g, 70%) as a whitesolid. ¹H NMR (400 MHz, CDCl₃) δ 10.24 (s, 1H), 7.81 (d, J=8.8 Hz, 1H),7.20 (dd, J=8.8, 2.8 Hz, 1H), 7.13 (d, J=2.8 Hz, 1H), 7.07 (s, 1H), 5.89(br s, 1H), 5.85-5.72 (m, 2H), 5.39 (d, J=8.4 Hz, 1H), 5.26 (d, J=17.2Hz, 1H), 5.14 (d, J=11.6 Hz, 1H), 5.01-4.90 (m, 2H), 4.45 (t, J=8.4 Hz,1H), 4.38-4.32 (m, 1H), 4.21 (d, J=12.0 Hz, 1H), 4.02 (dd, J=11.6, 4.0Hz, 1H), 3.93 (s, 3H), 2.95-2.89 (m, 1H), 2.56-2.48 (m, 5H), 2.13 (q,J=8.4 Hz, 1H), 2.05-1.99 (m, 3H), 1.74-1.66 (m, 1H), 1.62-1.54 (m, 1H),1.46-1.22 (m, 18H), 1.07-1.02 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ173.70, 172.41, 168.53, 160.32, 155.63, 155.17, 144.38, 140.88, 138.83,134.23, 132.47, 128.89, 118.92, 118.57, 114.44, 105.94, 79.76, 74.63,60.33, 55.69, 53.16, 52.29, 41.56, 35.18, 34.26, 33.66, 32.20, 31.13,28.76, 28.66, 28.25, 25.19, 23.59, 19.84, 6.48, 6.00 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₃₈H₅₃N₆O₉S, 769.3589; found 769.3579.

tert-Butyl((S)-1-((2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(17b)

The same procedure was used as described above for compound 16b. Acid13b (1.60 g, 2.9 mmol) was coupled with amine salt 15 (0.98 g, 3.5 mmol)using DIEA (2.0 mL, 11.5 mmol) and HATU (1.75 g, 4.6 mmol) to providethe bis-olefin compound 17b (1.50 g, 66%) as a white solid. ¹H NMR (400MHz, CDCl₃) δ 10.02 (s, 1H), 7.81 (d, J=8.8 Hz, 1H), 7.18 (dd, J=8.8,2.8 Hz, 1H), 7.13 (d, J=2.8 Hz, 1H), 7.11 (s, 1H), 5.88 (br s, 1H),5.82-5.72 (m, 2H), 5.42 (d, J=9.2 Hz, 1H), 5.26 (d, J=17.2 Hz, 1H), 5.14(d, J=11.6 Hz, 1H), 5.00-4.90 (m, 2H), 4.50 (t, J=8.4 Hz, 1H), 4.39-4.33(m, 1H), 4.18 (d, J=11.6 Hz, 1H), 4.02 (dd, J=11.6, 4.0 Hz, 1H), 3.93(s, 3H), 2.58-2.50 (m, 5H), 2.10 (q, J=8.4 Hz, 1H), 2.05-1.98 (m, 3H),1.73-1.58 (m, 4H), 1.49 (s, 3H), 1.44-1.24 (m, 16H), 0.92-0.86 (m, 1H),0.84-0.78 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 173.65, 172.52, 167.55,160.31, 155.70, 155.16, 144.41, 140.87, 138.83, 134.33, 132.61, 128.96,118.87, 118.54, 114.41, 105.96, 79.73, 74.59, 60.30, 55.67, 53.15,52.37, 41.73, 36.56, 35.16, 34.25, 33.62, 32.24, 28.71, 28.67, 28.26,25.31, 23.42, 19.84, 18.37, 14.27, 13.26 ppm; HRMS (ESI) m/z: [M+H]⁺calcd for C₃₉H₅₅N₆O₉S, 783.3746; found 783.3734.

tert-Butyl((S)-1-((2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(16c)

The same procedure was used as described above for compound 16b. Ester12c (1.80 g, 3.0 mmol) was treated with LiOH.H₂O to afford acid 13c,which was coupled with amine salt 14 (0.96 g, 3.6 mmol) using DIEA (2.0mL, 12.1 mmol) and HATU (1.70 g, 4.5 mmol) to provide the bis-olefincompound 16c (1.75 g, 74%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ10.25 (s, 1H), 7.82 (d, J=8.8 Hz, 1H), 7.26-7.23 (m, 1H), 7.17 (d, J=2.8Hz, 1H), 6.99 (s, 1H), 5.88-5.74 (m, 3H), 5.33 (d, J=8.8 Hz, 1H), 5.28(d, J=17.2 Hz, 1H), 5.16 (d, J=10.4 Hz, 1H), 5.01-4.90 (m, 2H), 4.53 (t,J=8.4 Hz, 1H), 4.37-4.32 (m, 1H), 4.28 (d, J=11.6 Hz, 1H), 4.03 (dd,J=12, 4.0 Hz, 1H), 3.96 (s, 3H), 2.96-2.90 (m, 1H), 2.60-2.54 (m, 2H),2.14 (q, J=8.8 Hz, 1H), 2.07-2.00 (m, 3H), 1.76-1.54 (m, 2H), 1.47-1.23(m, 18H), 1.08-1.02 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 174.01,172.48, 168.59, 161.61, 155.84, 152.31, 141.06, 139.09, 136.14, 134.39,132.66, 129.16, 120.43, 118.81, 114.66, 106.03, 80.05, 76.19, 60.64,56.05, 53.09, 52.56, 41.86, 35.44, 34.41, 33.90, 32.46, 31.39, 28.99,28.89, 28.46, 25.44, 23.80, 6.67, 6.27 ppm; HRMS (ESI) m/z: [M+H]⁺ calcdfor C₃₇H₅₀ClN₆O₉S, 789.3043; found 789.3030.

tert-Butyl((S)-1-((2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(17c)

The same procedure was used as described above for compound 16b. Ester12c (1.80 g, 3.0 mmol) was treated with LiOH.H₂O to afford acid 13c,which was coupled with amine salt 15 (1.0 g, 3.6 mmol) using DIEA (2.0mL, 12.1 mmol) and HATU (1.70 g, 4.5 mmol) to provide the bis-olefincompound 17c (1.85 g, 77%) as a white solid. ¹H NMR (500 MHz, CDCl₃) δ10.01 (s, 1H), 7.82 (d, J=9.0 Hz, 1H), 7.26-7.23 (m, 1H), 7.17 (d, J=2.5Hz, 1H), 7.02 (s, 1H), 5.87 (br s, 1H), 5.82-5.74 (m 2H), 5.36 (d, J=8.8Hz, 1H), 5.28 (d, J=17.0 Hz, 1H), 5.15 (d, J=11.2 Hz, 1H), 5.00-4.96 (m,1H), 4.94-4.91 (m, 1H), 4.53 (t, J=8.4 Hz, 1H), 4.37-4.32 (m, 1H), 4.24(d, J=11.5 Hz, 1H), 4.03 (dd, J=12.0, 4.0 Hz, 1H), 3.96 (s, 3H),2.61-2.53 (m, 2H), 2.12 (q, J=8.8 Hz, 1H), 2.05-2.00 (m, 3H), 1.74-1.58(m, 4H), 1.50 (s, 3H), 1.47-1.24 (m, 16H), 0.92-0.86 (m, 1H), 0.85-0.80(m, 1H); ¹³C NMR (125 MHz, CDCl₃) δ 173.74, 172.32, 167.42, 161.39,155.68, 152.09, 140.85, 138.88, 135.93, 134.20, 132.59, 128.95, 120.19,118.57, 114.41, 105.83, 79.79, 75.95, 60.39, 55.83, 52.86, 52.40, 41.79,36.59, 35.21, 34.16, 33.65, 32.30, 28.73, 28.69, 28.27, 25.34, 23.44,18.41, 14.24, 13.39 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₈H₅₂ClN₆O₉S,803.3200; found 803.3194.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(16e)

The same procedure was used as described above for compound 16b. Ester12e (2.0 g, 3.3 mmol) was treated with LiOH.H₂O to afford acid 13e,which was coupled with amine salt 14 (1.20 g, 4.5 mmol) using DIEA (2.25mL, 13.6 mmol) and HATU (1.90 g, 5.0 mmol) to provide the bis-olefincompound 16e (1.85 g, 70%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ10.25 (s, 1H), 7.85 (d, J=8.8 Hz, 1H), 7.19 (dd, J=8.8, 2.8 Hz, 1H),7.12 (d, J=2.8 Hz, 1H), 7.01 (s, 1H), 5.92 (br s, 1H), 5.84-5.73 (m,2H), 5.34 (d, J=8.8 Hz, 1H), 5.27 (d, J=17.2 Hz, 1H), 5.14 (d, J=11.6Hz, 1H), 5.01-4.89 (m, 2H), 4.48 (t, J=8.4 Hz, 1H), 4.40-4.33 (m, 1H),4.18 (d, J=11.6 Hz, 1H), 4.02 (dd, J=11.6, 7.2 Hz, 1H), 3.93 (s, 3H),3.40-3.33 (m, 1H), 2.96-2.90 (m, 1H), 2.56-2.52 (m, 2H), 2.12 (q, J=8.8Hz, 1H), 2.06-1.99 (m, 3H), 1.75-1.54 (m, 2H), 1.46-1.23 (m, 24H),1.07-1.02 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.80, 172.33,168.47, 160.28, 155.64, 154.23, 151.76, 140.49, 138.84, 134.43, 132.48,129.41, 118.68, 118.54, 114.43, 105.76, 79.75, 74.33, 60.39, 55.67,53.21, 52.38, 41.58, 35.22, 34.24, 33.65, 32.17, 31.15, 30.63, 28.75,28.65, 28.23, 25.22, 23.59, 20.61, 20.41, 6.45, 6.02 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₄₀H₅₇N₆O₉S, 797.3902; found 797.3906.

tert-Butyl((S)-1-((2S,4R)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(17e)

The same procedure was used as described above for compound 16b. Ester12e (2.0 g, 3.3 mmol) was treated with LiOH.H₂O to afford acid 13e,which was coupled with amine salt 15 (1.27 g, 4.5 mmol) using DIEA (2.25mL, 13.6 mmol) and HATU (1.90 g, 5.0 mmol) to provide the bis-olefincompound 17e (2.0 g, 75%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ10.03 (s, 1H), 7.85 (d, J=9.2 Hz, 1H), 7.19 (dd, J=9.2, 2.8 Hz, 1H),7.12 (d, J=2.8 Hz, 1H), 7.03 (s, 1H), 5.92 (br s, 1H), 5.84-5.73 (m,2H), 5.36 (d, J=8.8 Hz, 1H), 5.27 (d, J=17.2 Hz, 1H), 5.14 (d, J=10.8Hz, 1H), 5.01-4.89 (m, 2H), 4.47 (t, J=7.6 Hz, 1H), 4.40-4.33 (m, 1H),4.15 (d, J=11.6 Hz, 1H), 4.02 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H),3.40-3.33 (m, 1H), 2.57-2.52 (m, 2H), 2.12 (q, J=8.4 Hz, 1H), 2.05-1.99(m, 3H), 1.76-1.58 (m, 4H), 1.49 (s, 3H), 1.45-1.20 (m, 22H), 0.92-0.87(m, 1H), 0.85-0.79 (m, 1H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.79,172.38, 167.50, 160.28, 155.71, 154.23, 151.76, 140.49, 138.85, 134.43,132.61, 129.42, 118.69, 118.54, 114.41, 105.76, 79.72, 74.32, 60.40,55.68, 53.19, 52.47, 41.71, 36.56, 35.24, 34.22, 33.64, 32.18, 30.61,28.70, 28.67, 28.25, 25.35, 23.51, 20.63, 20.42, 18.38, 14.26, 13.31;HRMS (ESI) m/z: [M+H]⁺ calcd for C₄₁H₅₉N₆O₉S, 811.4059; found 811.4043.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-(thiophen-2-yl)quinoxalin-2-yl)oxy)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(16f)

The same procedure was used as described above for compound 16b. Ester12f (1.85 g, 3.0 mmol) was treated with LiOH.H₂O to afford acid 13f,which was coupled with amine salt 14 (0.96 g, 3.6 mmol) using DIEA (2.0mL, 12.1 mmol) and HATU (1.70 g, 4.5 mmol) to provide the bis-olefincompound 16f (1.60 g, 66%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ10.23 (s, 1H), 8.10 (d, J=3.2 Hz, 1H), 8.01 (dd, J=8.0, 1.2 Hz, 1H),7.79 (dd, J=8.8, 1.6 Hz, 1H), 7.65-7.56 (m, 2H), 7.53 (d, J=5.2 Hz, 1H),7.17 (dd, J=4.8, 4.0 Hz, 1H), 7.11 (s, 1H), 6.08 (br s, 1H), 5.83-5.73(m, 2H), 5.35 (d, J=8.8 Hz, 1H), 5.26 (dd, J=16.8, 1.2 Hz, 1H), 5.13(dd, J=10.4, 1.2 Hz, 1H), 5.01-4.90 (m, 2H), 4.54 (t, J=8.8 Hz, 1H),4.46-4.39 (m, 1H), 4.34 (d, J=12.4 Hz, 1H), 4.07 (dd, J=12.0, 3.6 Hz,1H), 2.95-2.87 (m, 1H), 2.68-2.56 (m, 2H), 2.10 (q, J=8.8 Hz, 1H),2.05-1.98 (m, 3H), 1.75-1.55 (m, 2H), 1.45-1.16 (m, 18H), 1.06-0.99 (m,2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.83, 172.34, 168.51, 155.70,152.05, 140.39, 139.17, 138.93, 138.86, 138.72, 132.47, 130.46, 130.35,129.56, 128.57, 128.13, 127.54, 126.72, 118.54, 114.44, 79.73, 75.39,60.32, 53.23, 52.51, 41.57, 35.14, 34.10, 33.66, 31.99, 31.14, 28.75,28.67, 28.26, 25.34, 23.56, 6.46, 6.03 ppm; HRMS (ESI) m/z: [M+H]⁺ calcdfor C₄₀H₅₁N₆O₈S2, 807.3204; found 807.3214.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-ethylquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(16g)

The same procedure was used as described above for compound 16b. Ester12g (1.95 g, 3.5 mmol) was treated with LiOH.H₂O to afford acid 13g,which was coupled with amine salt 14 (1.10 g, 4.1 mmol) using DIEA (2.30mL, 14.0 mmol) and HATU (2.0 g, 5.3 mmol) to provide the bis-olefincompound 16g (2.0 g, 76%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ10.24 (s, 1H), 7.96 (d, J=8.4 Hz, 1H), 7.78 (d, J=8.0 Hz, 1H), 7.63-7.53(m, 2H), 7.05 (s, 1H), 5.93 (br s, 1H), 5.85-5.73 (m, 2H), 5.35 (d,J=8.4 Hz, 1H), 5.27 (d, J=17.2 Hz, 1H), 5.14 (d, J=10.8 Hz, 1H),5.00-4.90 (m, 2H), 4.48 (t, J=8.0 Hz, 1H), 4.37-4.32 (m, 1H), 4.20 (d,J=12.0 Hz, 1H), 4.03 (dd, J=12.0, 4.0 Hz, 1H), 2.96-2.89 (m, 3H),2.57-2.52 (m, 2H), 2.12 (q, J=8.8 Hz, 1H), 2.05-1.99 (m, 2H), 1.75-1.54(m, 2H), 1.46-1.17 (m, 22H), 1.08-1.02 (m, 2H) ppm; ¹³C NMR (100 MHz,CDCl₃) δ 173.81, 172.33, 168.51, 155.64, 154.33, 151.84, 139.16, 138.91,138.84, 132.48, 129.11, 128.31, 126.92, 126.86, 118.54, 114.44, 79.74,74.56, 60.33, 53.16, 52.35, 41.56, 35.22, 34.18, 33.65, 32.14, 31.13,28.74, 28.65, 28.23, 26.73, 25.24, 23.62, 11.42, 6.47, 6.00 ppm; HRMS(ESI) m/z: [M+H]⁺ calcd for C₃₈H₅₃N₆O₈S, 753.3640; found 753.3636.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(18b)

A degassed solution of bis-olefin 16b (1.57 g, 2.0 mmol) in 1,2-DCE (310mL) was heated to 50° C. under argon, then Zhan 1b catalyst (0.150 g,0.20 mmol) was added in two portions over 10 min. The resulting reactionmixture was heated to 70° C. and stirred for 6 h. The reaction mixturewas cooled to room temperature and solvents were evaporated underreduced pressure. The residue was purified by flash chromatography using50-90% EtOAc/hexanes as the eluent to yield the P1-P3 macrocyclicproduct 18b (0.67 g, 45%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃)δ 10.28 (s, 1H), 7.80 (d, J=9.6 Hz, 1H), 7.19-7.16 (m, 2H), 6.88 (s,1H), 5.89 (br s, 1H), 5.69 (q, J=9.2 Hz, 1H), 5.12 (d, J=8.0 Hz, 1H),4.97 (t, J=9.2 Hz, 1H), 4.61 (t, J=8.0 Hz, 1H), 4.51 (d, J=12.0 Hz, 1H),4.28-4.22 (m, 1H), 4.01 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H),2.94-2.86 (m, 1H), 2.70-2.48 (m, 6H), 2.31 (q, J=8.4 Hz, 1H), 1.94-1.68(m, 2H), 1.60-1.22 (m, 19H), 1.16-1.06 (m, 2H), 0.95-0.89 (m, 1H) ppm;¹³C NMR (100 MHz, CDCl₃) δ 177.14, 173.33, 168.0, 160.31, 155.32,155.03, 144.49, 141.01, 136.30, 134.24, 128.68, 124.47, 118.90, 105.97,79.85, 74.84, 59.44, 55.72, 53.06, 51.96, 44.57, 34.58, 32.72, 31.02,29.73, 28.15, 27.10, 27.05, 26.01, 22.18, 20.96, 19.73, 6.67, 6.12 ppm;HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₆H₄₉N₆O₉S, 741.3276; found 741.3255.Anal. RP-HPLC: t_(R) 12.71 min, purity 99%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(19b)

The same procedure was used as described above for compound 18b.Bis-olefin 17b (1.50 g, 1.9 mmol) was treated with Zhan 1b catalyst(0.150 g, 0.20 mmol) in 1,2-DCE (300 mL) to provide the P1-P3macrocyclic compound 19b (1.0 g, 70%) as an off-white solid. ¹H NMR (400MHz, CDCl₃) δ 10.16 (s, 1H), 7.82 (d, J=9.2 Hz, 1H), 7.19-7.16 (m, 2H),6.92 (s, 1H), 5.88 (br s, 1H), 5.69 (q, J=9.2 Hz, 1H), 5.12 (d, J=7.6Hz, 1H), 4.99 (t, J=8.8 Hz, 1H), 4.61 (t, J=8.0 Hz, 1H), 4.51 (d, J=11.2Hz, 1H), 4.28-4.22 (m, 1H), 4.03 (dd, J=11.2, 4.0 Hz, 1H), 3.95 (s, 3H),2.70-2.50 (m, 6H), 2.31 (q, J=8.8 Hz, 1H), 1.92-1.66 (m, 4H), 1.60-1.20(m, 21H), 0.85-0.78 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.16,173.33, 166.94, 160.33, 155.32, 155.04, 144.46, 141.03, 134.20, 136.25,128.66, 124.89, 118.93, 105.98, 79.85, 74.88, 59.46, 55.72, 53.08,51.97, 44.73, 36.43, 34.61, 32.72, 29.65, 28.15, 27.06, 26.07, 22.21,20.96, 19.71, 18.17, 14.51, 12.51 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₇H₅₁N₆O₉S, 755.3433; found 755.3404. Anal. HPLC: t_(R) 13.57 min,purity 99%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-14a-((cyclopropylsulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(18c)

The same procedure was used as described above for compound 18b.Bis-olefin 16c (1.50 g, 1.9 mmol) was treated with Zhan 1b catalyst(0.150 g, 0.20 mmol) in 1,2-DCE (300 mL) to provide the P1-P3macrocyclic compound 18c (0.73 g, 500%) as an off-white solid. ¹H NMR(400 MHz, CDCl₃) δ 10.30 (s, 1H), 7.78 (d, J=9.6 Hz, 1H), 7.25-7.20 (m,2H), 7.00 (s, 1H), 5.86 (s, 1H), 5.68 (q, J=9.2 Hz, 1H), 5.19 (d, J=7.6Hz, 1H), 4.95 (t, J=9.2 Hz, 1H), 4.65 (t, J=8.0 Hz, 1H), 4.59 (d, J=11.6Hz, 1H), 4.26-4.22 (m, 1H), 4.03 (dd, J=11.6, 4.0 Hz, 1H), 3.95 (s, 3H),2.94-2.87 (m, 1H), 2.68-2.51 (m, 3H), 2.31 (q, J=8.8 Hz, 1H), 1.94-1.74(m, 2H), 1.60-1.20 (m, 19H), 1.17-1.04 (m, 2H), 0.96-0.89 (in, 1H) ppm;¹³C NMR (100 MHz, CDCl₃) δ 177.32, 173.48, 168.24, 161.52, 155.30,152.45, 141.15, 136.53, 136.25, 134.26, 129.02, 124.71, 120.31, 106.06,80.14, 76.38, 59.71, 56.08, 52.90, 52.15, 44.80, 34.73, 32.85, 31.28,29.88, 28.38, 27.36, 27.31, 26.29, 22.46, 21.13, 6.90, 6.35 ppm. HRMS(ESI) m/z: [M+H]⁺ calcd for C₃₅H₄₆ClN₆O₉S, 761.2730; found 761.2706.Anal. HPLC: t_(R) 14.28 min, purity 96%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(19c)

The same procedure was used as described above for compound 18b.Bis-olefin 17c (1.20 g, 1.5 mmol) was treated with Zhan 1b catalyst(0.150 g, 0.20 mmol) in 1,2-DCE (300 mL) to provide the P1-P3macrocyclic compound 19c (1.0 g, 86%) as an off-white solid. ¹H NMR (400MHz, CDCl₃) δ 10.20 (s, 1H), 7.78 (d, J=10.0 Hz, 1H), 7.23-7.20 (m, 2H),7.07 (s, 1H), 5.85 (br s, 1H), 5.67 (q, J=8.4 Hz, 1H), 5.25 (d, J=7.2Hz, 1H), 4.96 (t, J=9.2 Hz, 1H), 4.67-4.58 (m, 2H), 4.28-4.22 (m, 1H),4.04 (dd, J=11.2, 3.2 Hz, 1H), 3.96 (s, 3H), 2.68-2.62 (m, 2H),2.60-2.50 (m, 1H), 2.33 (q, J=8.0 Hz, 1H), 1.91-1.72 (m, 4H), 1.60-1.20(m, 21H), 0.84-0.78 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.18,173.18, 167.07, 161.27, 155.06, 152.21, 140.92, 136.27, 135.99, 134.0,128.76, 124.88, 120.09, 105.81, 79.90, 76.21, 59.51, 55.85, 52.69,51.89, 44.70, 36.41, 34.54, 32.57, 29.48, 28.25, 28.15, 27.11, 26.15,22.22, 20.83, 18.17, 14.51, 12.50 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₆H₄₈ClN₆O₉S, 775.2887; found 775.2870. Anal. HPLC: t_(R) 14.69 min,purity 97%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(18e)

The same procedure was used as described above for compound 18b.Bis-olefin 16e (1.80 g, 2.3 mmol) was treated with Zhan 1b catalyst(0.150 g, 0.20 mmol) in 1,2-DCE (350 mL) to provide the P1-P3macrocyclic compound 18e (0.95 g, 58%) as an off-white solid. ¹H NMR(400 MHz, CDCl₃) δ 10.28 (s, 1H), 7.83 (d, J=9.6 Hz 1H), 7.20-7.15 (m,2H), 6.94 (s, 1H), 5.91 (s, 1H), 5.70 (q, J=8.4 Hz, 1H), 5.20 (d, J=8.0Hz, 1H), 4.97 (t, J=8.8 Hz, 1H), 4.58 (t, J=8.0 Hz, 1H), 4.46 (d, J=12.0Hz, 1H), 4.33-4.26 (m, 1H), 4.03 (dd, J=12.0, 4.4 Hz, 1H), 3.94 (s, 3H),3.41-3.33 (m, 1H), 2.93-2.86 (m, 1H), 2.66-2.50 (m, 3H), 2.34 (q, J=8.8Hz, 1H), 1.93-1.74 (m, 2H), 1.60-1.05, m, 27H), 0.95-0.88 (m, 1H) ppm;¹³C NMR (100 MHz, CDCl₃) δ 177.22, 173.13, 168.13, 160.22, 154.96,154.36, 151.82, 140.61, 136.32, 134.31, 129.28, 124.45, 118.61, 105.79,79.81, 74.55, 59.47, 55.71, 53.12, 51.86, 44.52, 34.74, 32.91, 31.00,30.58, 29.65, 28.18, 27.16, 27.11, 26.12, 22.14, 20.89, 20.51, 20.42,6.67, 6.10 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₈H₅₃N₆O₉S, 769.3589;found 769.3565. Anal. HPLC: t_(R) 15.82 min, purity 98%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(19e)

The same procedure was used as described above for compound 18b.Bis-olefin 17e (1.90 g, 2.3 mmol) was treated with Zhan 1b catalyst(0.20 g, 0.27 mmol) in 1,2-DCE (350 mL) to provide the P1-P3 macrocycliccompound 19e (1.1 g, 60%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃)δ 10.15 (s, 1H), 7.83 (d, J=9.6 Hz, 1H), 7.19-7.15 (m, 2H), 6.95 (s,1H), 5.91 (s, 1H), 5.70 (q, J=8.4 Hz, 1H), 5.19 (d, J=8.0 Hz, 1H), 4.99(t, J=9.6 Hz, 1H), 4.57 (t, J=8.0 Hz, 1H), 4.47 (d, J=11.6 Hz, 1H),4.34-4.27 (m, 1H), 4.06 (dd, J=11.2, 4.0 Hz, 1H), 3.94 (s, 3H),3.41-3.34 (m, 1H), 2.68-2.48 (m, 3H), 2.34 (q, J=8.4 Hz, 1H), 1.93-1.70(m, 4H), 1.62-1.17 (m, 27H), 0.84-0.78 (m, 2H) ppm; ¹³C NMR (100 MHz,CDCl₃) δ 177.19, 173.14, 167.04, 160.24, 154.96, 154.36, 151.79, 140.62,136.25, 134.28, 129.25, 124.88, 118.64, 105.81, 79.81, 74.61, 59.49,55.71, 53.15, 51.87, 44.68, 36.43, 34.75, 32.91, 30.59, 29.59, 28.17,27.14, 26.17, 22.18, 20.91, 20.50, 20.42, 18.17, 14.50, 12.49 ppm; HRMS(ESI) m/z: [M+H]⁺ calcd for C₃₉H₅₅N₆O₉S, 783.3746; found 783.3722. Anal.HPLC: t_(R) 16.46 min, purity 98%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-5,16-dioxo-2-((3-(thiophen-2-yl)quinoxalin-2-yl)oxy)-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(18f)

The same procedure was used as described above for compound 18b.Bis-olefin 16f (0.60 g, 0.7 mmol) was treated with Zhan 1b catalyst(0.10 g, 0.13 mmol) in 1,2-DCE (200 mL) to provide the P1-P3 macrocycliccompound 18f (0.35 g, 61%) as an off-white solid. ¹H NMR (400 MHz,CDCl₃) δ 10.28 (s, 1H), 8.08 (d, J=3.2 Hz, 1H), 7.99 (d, J=7.2 Hz, 1H),7.83 (dd, J=8.4, 1.2 Hz, 1H), 7.65-7.55 (m, 2H), 7.49 (d, J=4.4 Hz, 1H),7.14 (t, J=4.0 Hz, 1H), 6.96 (s, 1H), 6.08 (br s, 1H), 5.66 (q, J=9.2Hz, 1H), 5.16 (d, J=8.4 Hz, 1H), 4.95 (t, J=10.0 Hz, 1H), 4.69 (t, J=8.0Hz, 1H), 4.63 (d, J=12.4 Hz, 1H), 4.34-4.27 (m, 1H), 4.08 (dd, J=12.0,4.0 Hz, 1H), 2.94-2.86 (m, 1H), 2.76-2.69 (m, 2H), 2.58-2.48 (m, 1H),2.29 (q, J=8.4 Hz, 1H), 1.92-1.74 (m, 2H), 1.64-1.04 (m, 20H), 0.96-0.88(m, 1H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.19, 173.43, 168.20, 155.16,152.45, 140.65, 139.81, 139.10, 139.07, 136.53, 130.53, 130.33, 129.72,128.72, 128.30, 127.60, 127.07, 124.72, 80.06, 75.73, 59.75, 53.41,52.21, 44.79, 34.84, 33.13, 31.27, 29.96, 28.30, 27.41, 27.23, 26.21,22.54, 21.17, 6.93, 6.37 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₈H₄₇N₆O₈S₂, 779.2891; found 779.2873. Anal. HPLC: t_(R) 15.96 min,purity 97%.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((3-ethylquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(18g)

The same procedure was used as described above for compound 18b.Bis-olefin 16g (1.80 g, 2.4 mmol) was treated with Zhan 1b catalyst(0.20 g, 0.30 mmol) in 1,2-DCE (350 mL) to provide the P1-P3 macrocycliccompound 18g (1.05 g, 60%) as an off-white solid. ¹H NMR (400 MHz,CDCl₃) δ 10.32 (s, 1H), 7.94 (d, J=8.0 Hz, 1H), 7.80 (dd, J=8.0. 1.2 Hz1H), 7.62-7.51 (m, 2H), 7.02 (s, 1H), 5.91 (br s, 1H), 5.67 (q, J=8.4Hz, 1H), 5.19 (d, J=7.6 Hz, 1H), 4.95 (t, J=9.2 Hz, 1H), 4.61 (t, J=8.0Hz, 1H), 4.51 (d, J=11.6 Hz, 1H), 4.27-22 (m, 1H), 4.03 (dd, J=11.2, 3.6Hz, 1H), 2.94-2.85 (m, 3H), 2.65-2.52 (m, 3H), 2.32 (q, J=8.4 Hz, 1H),1.91-1.76 (m, 2H), 1.56-1.20 (m, 20H), 1.15-1.04 (m, 4H), 0.93-0.87 (m,1H) ppm; ¹³C NMR (400 MHz, CDCl₃) δ 177.23, 173.20, 168.17, 154.96,154.48, 152.00, 139.29, 138.81, 136.32, 128.98, 128.20, 126.95, 126.68,124.50, 79.77, 74.79, 59.46, 53.16, 51.91, 44.57, 34.64, 32.81, 30.99,29.66, 28.13, 27.09, 26.68, 26.06, 22.14, 20.94, 11.31, 6.66, 6.10 ppm;HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₆H₄₉N₆O₈S, 725.3327; found 725.3301.Anal. HPLC: t_(R) 14.40 min, purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22b)

Compound 18b (0.32 g, 0.43 mmol) was treated with a solution of 4 N HClin 1,4-dioxane (10 mL). The reaction mixture was stirred at roomtemperature for 3 h, and then concentrated under reduced pressure, andthe residue was dried under high vacuum. The off-white solid wastriturated with diethyl ether (3×10 mL) and dried under high vacuum toyield the amine salt 20b (0.29 g, 100%) as a white powder.

A solution of the above amine salt 20b (0.29 g, 0.43 mmol) in anhydrousCH₃CN (13 mL) was treated with DIEA (0.28 mL, 1.7 mmol) andN-(cyclopentyloxycarbonyloxy)-succinimide (0.108 g, 0.48 mmol). Thereaction mixture was stirred at room temperature for 36 h, thenconcentrated under reduced pressure and dried under high vacuum. Theresidue was purified by flash chromatography using 50-90% EtOAc/hexanesas the eluent to provide the target compound 22b (0.29 g, 90%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.29 (s, 1H), 7.79 (d, J=9.6 Hz,1H), 7.20-7.16 (m, 2H), 6.98 (s, 1H), 5.91 (br s, 1H), 5.68 (q, J=8.8Hz, 1H), 5.24 (d, J=8.0 Hz, 1H), 4.96 (t, J=8.8 Hz, 1H), 4.88-4.84 (brs, 1H), 4.62 (t, J=7.6 Hz, 1H), 4.42 (d, J=11.6 Hz, 1H), 4.33-4.27 (m,1H), 4.04 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H), 2.94-2.86 (m, 1H),2.69-2.48 (m, 5H), 2.29 (q, J=8.4 Hz, 1H), 1.93-1.23 (m, 21H), 1.17-1.05(m, 2H), 0.96-0.87 (m, 1H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.18,173.03, 168.05, 160.22, 155.69, 155.32, 144.67, 140.95, 136.25, 134.26,128.85, 124.44, 118.79, 105.97, 77.89, 74.63, 59.45, 55.72, 53.02,52.20, 44.51, 34.55, 32.72, 32.65, 32.59, 31.02, 29.74, 27.21, 27.03,26.04, 23.60, 23.57, 22.15, 20.90, 19.86, 6.67, 6.12 ppm; HRMS (ESI)m/z: calcd for C₃₇H₄₉N₆O₉S [M+H]⁺ 753.3276; found 753.3252. Anal. HPLC:t_(R) 13.05 min, purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(23b)

The same procedure was used as described above for compound 22b.Compound 19b (0.44 g, 0.58 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 21b, which was treated with DIEA (0.38 mL,2.3 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66mmol) to provide the target compound 23b (0.32 g, 72%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.17 (s, 1H), 7.79 (d, J=10.0 Hz, 1H),7.20-7.16 (m, 2H), 6.96 (s, 1H), 5.91 (br s, 1H), 5.69 (q, J=8.8 Hz,1H), 5.25 (d, J=8.0 Hz, 1H), 4.98 (t, J=9.6 Hz, 1H), 4.88-4.83 (m, 1H),4.61 (t, J=8.0 Hz, 1H), 4.43 (d, J=11.2 Hz, 1H), 4.34-4.27 (m, 1H), 4.05(dd, J=10.8, 4.0 Hz, 1H), 3.94 (s, 3H), 2.70-2.48 (m, 5H), 2.30 (q,J=8.8 Hz, 1H), 1.93-1.23 (m, 25H), 0.85-0.78 (m, 2H) ppm; ¹³C NMR (100MHz, CDCl₃) δ 177.20, 173.01, 167.0, 160.22, 155.68, 155.31, 144.67,140.96, 136.21, 134.27, 128.85, 124.86, 118.79, 105.98, 77.89, 74.67,59.48, 55.72, 53.05, 52.20, 44.67, 36.43, 34.58, 32.72, 32.65, 32.57,29.64, 27.17, 27.04, 26.09, 23.59, 23.57, 22.18, 20.91, 19.85, 18.17,14.49, 12.51 ppm; HRMS (ESI) m/z: calcd for C₃₈H₅₁N₆O₉S [M+H]⁺ 767.3433;found 767.3408. Anal. HPLC: t_(R) 13.88 min, purity 98%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-14a-((cyclopropylsulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22c)

The same procedure was used as described above for compound 22b.Compound 18c (0.40 g, 0.53 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 20c, which was treated with DIEA (0.35 mL,2.1 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66mmol) to provide the target compound 22c (0.34 g, 83%) as a white solid.¹H NMR (500 MHz, CDCl₃) δ 10.30 (s, 1H), 7.79 (d, J=9.0 Hz, 1H),7.23-7.20 (m, 2H), 7.11 (s, 1H), 5.89 (br s, 1H), 5.68 (q, J=9.0 Hz,1H), 5.30 (d, J=8.0 Hz, 1H), 4.96 (t, J=9.0 Hz, 1H), 4.84-4.80 (m, 1H),4.67 (t, J=7.6 Hz, 1H), 4.51 (d, J=11.4 Hz, 1H), 4.29 (t, J=7.6 Hz, 1H),4.04 (dd, J=11.0, 3.5 Hz, 1H), 3.95 (s, 3H), 2.93-2.87 (m, 1H),2.71-2.47 (m, 3H), 2.30 (q, J=8.5 Hz, 1H), 1.95-1.20 (m, 20H), 1.16-1.04(m, 2H), 0.95-0.87 (m, 1H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 177.11,173.01, 168.06, 161.31, 155.75, 152.29, 140.95, 136.22, 136.18, 134.08,128.77, 124.49, 120.08, 105.88, 77.98, 76.05, 59.48, 55.86, 52.62,52.19, 44.53, 34.43, 32.70, 32.62, 32.47, 31.07, 29.70, 27.23, 27.06,26.06, 23.59, 23.57, 22.25, 20.85, 6.67, 6.12 ppm; HRMS (ESI) m/z: calcdfor C₃₆H₄₆ClN₆O₉S [M+H]⁺ 773.2730; found 773.2714. Anal. HPLC: t_(R)14.35 min, purity 96%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(23c)

The same procedure was used as described above for compound 22b.Compound 19c (0.50 g, 0.64 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 21c, which was treated with DIEA (0.43 mL,2.6 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.20 g, 0.88mmol) to provide the target compound 23c (0.46 g, 91%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.22 (s, 1H), 7.78 (d, J=10.0 Hz, 1H),7.23-7.20 (m, 2H), 7.16 (s, 1H), 5.87 (br s, 1H), 5.66 (q, J=8.4 Hz,1H), 5.39 (d, J=7.2 Hz, 1H), 4.95 (t, J=9.6 Hz, 1H), 4.84-4.80 (m, 1H),4.65 (t, J=8.0 Hz, 1H), 4.53 (d, J=8.4 Hz, 1H), 4.32-4.26 (m, 1H), 4.04(dd, J=12.0, 4.0 Hz, 1H), 3.95 (s, 3H), 2.67-2.46 (m, 3H), 2.30 (q,J=8.4 Hz, 1H), 1.90-1.23 (m, 24H), 0.84-0.78 (m, 2H) ppm; ¹³C NMR (100MHz, CDCl₃) δ 177.18, 172.93, 167.03, 161.26, 155.73, 152.26, 140.93,136.22, 136.16, 134.04, 128.73, 124.86, 120.08, 105.84, 77.96, 76.06,59.52, 55.85, 52.61, 52.14, 44.68, 36.42, 34.45, 32.69, 32.60, 32.40,29.54, 27.14, 27.07, 26.12, 23.58, 23.55, 22.23, 20.85, 18.17, 14.50,12.52 ppm; HRMS (ESI) m/z: calcd for C₃₇H₄₈ClN₆O₉S [M+H]⁺ 787.2887;found 787.2872. Anal. HPLC: t_(R) 15.11 min, purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22e)

The same procedure was used as described above for compound 22b.Compound 18e (0.45 g, 0.58 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 20e, which was treated with DIEA (0.40 mL,2.4 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66mmol) to provide the target compound 22e (0.40 g, 88%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.29 (s, 1H), 7.84 (d, J=8.8 Hz 1H),7.20-7.16 (m, 2H), 6.94 (s, 1H), 5.93 (br s, 1H), 5.70 (q, J=8.4 Hz,1H), 5.28 (d, J=8.0 Hz 1H), 4.97 (t, J=8.8 Hz, 1H), 4.87-4.82 (m, 1H),4.59 (t, J=7.2 Hz, 1H), 4.44 (d, J=11.2 Hz, 1H), 4.36-4.30 (m, 1H), 4.04(dd, J=11.6, 7.6 Hz, 1H), 3.94 (s, 3H), 3.42-3.34 (m, 1H), 2.93-2.86 (m,1H), 2.70-2.48 (m, 3H), 2.32 (q, J=8.4 Hz, 1H), 1.94-1.21 (m, 26H),1.16-1.05 (m, 2H), 0.96-0.88 (m, 1H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ177.20, 172.97, 168.08, 160.25, 155.60, 154.40, 151.82, 140.65, 136.27,134.23, 129.18, 124.47, 118.65, 105.81, 77.81, 74.46, 59.49, 55.70,53.06, 52.13, 44.52, 34.63, 32.73, 32.57, 31.01, 30.63, 29.68, 27.17,27.06, 26.08, 23.56, 22.17, 20.91, 20.48, 20.43, 6.65, 6.10 ppm; HRMS(ESI) m/z: calcd for C₃₉H₅₃N₆O₉S [M+H]⁺ 781.3589; found 781.3569. Anal.HPLC: t_(R) 16.03 min, purity 98%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(23e)

The same procedure was used as described above for compound 22b.Compound 19e (0.45 g, 0.57 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 21e, which was treated with DIEA (0.40 mL,2.4 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66mmol) to provide the target compound 23e (0.40 g, 88%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.16 (s, 1H), 7.85 (d, J=8.8 Hz, 1H),7.21-7.16 (m, 2H), 6.90 (s, 1H), 5.93 (br s, 1H), 5.71 (q, J=8.4 Hz,1H), 5.25 (d, J=8.0 Hz 1H), 4.99 (t, J=8.8 Hz, 1H), 4.86-4.82 (m, 1H),4.58 (t, J=8.0 Hz, 1H), 4.46 (d, J=11.2 Hz, 1H), 4.36-4.29 (m, 1H), 4.05(dd, J=11.2, 3.6 Hz, 1H), 3.94 (s, 3H), 3.42-3.34 (m, 1H), 2.72-2.48 (m,3H), 2.32 (q, J=8.4 Hz, 1H), 1.94-1.21 (m, 30H), 0.86-0.78 (m, 2H) ppm;¹³C NMR (100 MHz, CDCl₃) δ 177.24, 172.94, 167.04, 160.25, 155.60,154.40, 151.81, 140.67, 136.23, 134.21, 129.17, 124.89, 118.66, 105.83,77.80, 74.52, 59.53, 55.71, 53.08, 52.13, 44.68, 36.43, 34.65, 32.72,32.56, 30.63, 29.59, 27.14, 27.08, 26.14, 23.55, 22.19, 20.92, 20.47,20.44, 18.17, 14.49, 12.47 ppm; HRMS (ESI) m/z: calcd for C₄₀H₅₅N₆O₉S[M+H]⁺ 795.3746; found 795.3723. Anal. HPLC: t_(R) 16.71 min, purity99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-5,16-dioxo-2-((3-(thiophen-2-yl)quinoxalin-2-yl)oxy)-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22f)

The same procedure was used as described above for compound 22b.Compound 18f (0.40 g, 0.51 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 20f, which was treated with DIEA (0.35 mL,2.1 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66mmol) to provide the target compound 22f (0.38 g, 94%) as an off-whitesolid. ¹H NMR (500 MHz, CDCl₃) δ 10.25 (s, 1H), 8.08 (s, 1H), 8.00 (d,J=8.0 Hz, 1H), 7.83 (d, J=8.0 Hz, 1H) 7.65-7.56 (m, 2H), 7.47 (d, J=4.0Hz, 1H), 7.12 (t, J=4.0 Hz, 1H), 6.93 (s, 1H), 6.11 (br s, 1H), 5.66 (q,J=8.8 Hz, 1H), 5.25 (d, J=8.0 Hz, 1H), 4.95 (t, J=9.0 Hz, 1H), 4.80-4.75(m, 1H), 4.68-4.61 (m, 2H), 4.37 (t, J=9.0 Hz, 1H), 4.08 (d, J=11.2 Hz,1H), 2.92-2.85 (m, 1H), 2.75-2.69 (m, 2H), 2.57-2.49 (m, 1H), 2.29 (q,J=8.6 Hz, 1H), 1.88-1.22 (m, 23H), 1.17-1.05 (m, 2H), 0.94-0.87 (m, 1H)ppm; ¹³C NMR (125 MHz, CDCl₃) δ 176.98, 173.11, 167.92, 155.68, 152.27,139.71, 138.90, 138.85, 136.28, 130.44, 130.04, 129.51, 128.48, 128.08,127.40, 126.84, 124.47, 77.90, 75.50, 59.51, 53.24, 52.26, 44.57, 34.61,32.89, 32.78, 32.48, 31.06, 29.74, 27.19, 27.01, 26.01, 23.58, 22.29,20.94, 6.68, 6.14 ppm; HRMS (ESI) m/z: calcd for C₃₉H₄₇N₆O₈S₂[M+H]⁺791.2891; found 791.2872. Anal. HPLC: t_(R) 16.39 min, purity 99%.

Cyclopentyl((2R,6S,13aS,14aR,16aS,Z)-14a-((cyclopropylsulfonyl)carbamoyl)-2-((3-ethylquinoxalin-2-yl)oxy)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(22g)

The same procedure was used as described above for compound 22b.Compound 18g (0.50 g, 0.69 mmol) was treated 4 N HCl in 1,4-dioxane (10mL) to yield the amine salt 20g, which was treated with DIEA (0.46 mL,2.8 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.18 g, 0.79mmol) to provide the target compound 22g (0.42 g, 83%) as a white solid.¹H NMR (400 MHz, CDCl₃) δ 10.31 (s, 1H), 7.95 (d, J=8.0 Hz, 1H), 7.81(d, J=8.0 Hz, 1H), 7.63-7.52 (m, 2H), 7.00 (s, 1H), 5.94 (br s, 1H),5.69 (q, J=8.4 Hz, 1H), 5.26 (d, J=8.0 Hz, 1H), 4.96 (t, J=9.6 Hz, 1H),4.83-4.78 (m, 1H), 4.62 (t, J=8.0 Hz, 1H), 4.46 (d, J=12.0 Hz, 1H),4.32-4.25 (m, 1H), 4.04 (dd, J=11.6, 3.6 Hz, 1H), 2.95-2.85 (m, 3H),2.66-2.50 (m, 3H), 2.30 (q, J=8.8 Hz, 1H), 1.93-1.05 (m, 25H), 0.95-0.88(m, 1H) ppm; ¹³C NMR (400 MHz, CDCl₃) δ 177.18, 173.05, 168.10, 155.62,154.51, 152.11, 139.30, 138.85, 136.29, 128.99, 128.18, 126.96, 126.72,124.50, 77.82, 74.68, 59.46, 53.12, 52.20, 44.55, 34.56, 32.69, 32.57,31.00, 29.70, 27.12, 27.03, 26.74, 26.02, 23.55, 22.17, 20.94, 11.37,6.66, 6.11 ppm; HRMS (ESI) m/z: calcd for C₃₇H₄₉N₆O₈S [M+H]⁺ 737.3327;found 737.3306. Anal. HPLC: t_(R) 14.64 min, purity 99%.

Expression and Purification of NS3/4A Constructs

The HCV GT1a NS3/4A protease gene described in the Bristol Myers Squibbpatent² was synthesized by GenScript and cloned into a PET28a expressionvector. The D168A gene was engineered using the site-directedmutagenesis protocol from Stratagene. Protein expression andpurification were carried out as previously described. Briefly,transformed Escherichia coli BL21(DE3) cells were grown in LB mediacontaining 30 μg/mL of kanamycin antibiotic at 37° C. After reaching anOD₆₀₀ of 0.8, cultures were induced with 1 mM IPTG and harvested after 4h of expression. Cells were pelleted by centrifugation, resuspended inResuspension buffer [50 mM phosphate buffer, 500 mM NaCl, 10% glycerol,2 mM β-ME, pH 7.5] and frozen at −80° C. for storage.

Cell pellets were thawed and lysed via cell disruptor (MicrofluidicsInc.) two times to ensure sufficient DNA shearing. Lysate wascentrifuged at 19,000 rpm, for 25 min at 4° C. The soluble fraction wasapplied to a nickel column (Qiagen) pre-equilibrated with Resuspensionbuffer. The beads and soluble fraction were incubated at 4° C. for 1.5 hand the lysate was allowed to flow through. Beads were washed withResuspension buffer supplemented with 20 mM imidazole and eluted withResuspension buffer supplemented with 200 mM imidazole. The eluent wasdialyzed overnight (MWCO 10 kD) to remove the imidazole, and the His-tagwas simultaneously removed with thrombin treatment. The eluate wasjudged >90% pure by polyacrylamide gel electrophoresis, concentrated,flash frozen, and stored at −80° C.

The HCV GT3a NS3/4A protease gene was synthesized by GenScript.Transformed Escherichia coli BL21(DE3) cells were grown in LB mediacontaining 30 μg/mL of kanamycin antibiotic at 37° C. After reaching anOD₆₀₀ 0.7, cultures were incubated at 4° C. for 20 min before beinginduced with 1 mM IPTG and placed at 18° C. for overnight expression.Cells were pelleted by centrifugation, resuspended in Resuspensionbuffer and frozen at −80° C. for storage.

Cell pellets were thawed and lysed via cell disruptor (MicrofluidicsInc.) two times to ensure sufficient DNA shearing and treated withDNaseI. The lysate was treated and purified using a nickel column asabove, with an additional wash with 1 M NaCl prior to elution. Theprotein was further purified using a HiLoad Superdex75 16/60 columnequilibrated with Resuspension buffer. The eluate was judged >90% pureby polyacrylamide gel electrophoresis, concentrated, flash frozen, andstored at −80° C.

Determination of the Inner Filter Effect

The inner filter effect (IFE) for the NS3/4A protease substrate wasdetermined using a previously described method. Briefly, fluorescenceend-point readings were taken for substrate concentrations between 0 μMand 20 μM. Afterward, free 5-FAM fluorophore was added to a finalconcentration of 25 μM to each substrate concentration and a secondround of fluorescence end-point readings was taken. The fluorescence offree 5-FAM was determined by subtracting the first fluorescence endpoint reading from the second round of readings. IFE corrections werethen calculated by dividing the free 5-FAM florescence at each substrateconcentration by the free 5-FAM florescence at zero substrate.

Determination of Michaelis-Menten (K) Constant

K_(m) constants for GT1 and D168A protease were previously determined.⁵The K_(m) of GT3 protease was determined using the following method. A20 μM concentration of substrate[Ac-DE-Dap(QXL520)-EE-Abu-γ-[COO]AS-C(5-FAMsp)-NH2] (AnaSpec) wasserially diluted into assay buffer [50 mM Tris, 5% glycerol, 10 mM DTT,0.6 mM LDAO, and 4% dimethyl sulfoxide] and proteolysis was initiated byrapid injection of 10 μL GT3 protease (final concentration 20 nM) in areaction volume of 60 μL. The fluorescence output from the substratecleavage product was measured kinetically using an EnVision plate reader(Perkin-Elmer) with excitation wavelength at 485 nm and emission at 530nm. Inner filter effect corrections were applied to the initialvelocities (V) at each substrate concentration. V_(o) versus substrateconcentration graphs were globally fit to the Michaelis-Menten equationto obtain the K_(m) value.

Enzyme Inhibition Assays

For each assay, 2 nM of NS3/4A protease (GT1, D168A and GT3) waspre-incubated at room temperature for 1 h with increasing concentrationof inhibitors in assay buffer [50 mM Tris, 5% glycerol, 10 mM DTT, 0.6mM LDAO, and 4% dimethyl sulfoxide]. Inhibition assays were performed innonbinding surface 96-well black half-area plates (Corning) in areaction volume of 60 μL. The proteolytic reaction was initiated by theinjection of 5 μL of HCV NS3/4A protease substrate (AnaSpec), to a finalconcentration of 200 nM and kinetically monitored using a Perkin ElmerEnVision plate reader (excitation at 485 nm, emission at 530 nm). Threeindependent data sets were collected for each inhibitor with eachprotease construct. Each inhibitor titration included at least 12inhibitor concentration points, which were globally fit to the Morrisonequation to obtain the K_(i) value.

Cell-Based Drug Susceptibility Assays

Mutations (R155K, A516T, D168A and D168V) were constructed bysite-directed mutagenesis using a Con1 (genotype 1b) luciferase reporterreplicon containing the H77 (genotype 1a) NS3 sequence. (Sarkar, et al.Biotechniques 1990, 8, 404-407.)

Replicon RNA of each protease variant was introduced into Huh7 cells byelectroporation. Replication was then assessed in the presence ofincreasing concentrations of protease inhibitors by measuring luciferaseactivity (relative light units) 96 h after electroporation. The drugconcentrations required to inhibit replicon replication by 50% (EC₅₀)were calculated directly from the drug inhibition curves.

Crystallization and Structure Determination

Protein expression and purification were carried out as previouslydescribed (see Supporting Information for details). (Romano, et al. PLOSPathog. 2012, 8, e1002832.) The Ni-NTA purified WT1a protein was thawed,concentrated to 3 mg/mL, and loaded on a HiLoad Superdex75 16/60 columnequilibrated with gel filtration buffer (25 mM MES, 500 mM NaCl, 10%glycerol, and 2 mM DTT, pH 6.5). The protease fractions were pooled andconcentrated to 25 mg/mL with an Amicon Ultra-15 10 kDa filter unit(Millipore). The concentrated samples were incubated for 1 h with 3:1molar excess of inhibitor. Diffraction-quality crystals were obtainedovernight by mixing equal volumes of concentrated protein solution withprecipitant solution (20-26% PEG-3350, 0.1 M sodium MES buffer, 4%ammonium sulfate, pH 6.5) at RT or 15° C. in 24-well VDX hanging droptrays. Crystals were harvested and data collected at 100 K. Cryogenicconditions contained the precipitant solution supplemented with 15%glycerol or ethylene glycol.

Diffraction data were collected using an in-house Rigaku X-ray systemwith a Saturn 944 detector. All datasets were processed using HKL-3000.Structures were solved by molecular replacement using PHASER. The WT-2complex structure (PDB code: 5EPN) was used as the starting structurefor all structure solutions. Model building and refinement wereperformed using Coot and PHENIX, respectively. The final structures wereevaluated with MolProbity prior to deposition in the PDB. To limit thepossibility of model bias throughout the refinement process, 5% of thedata were reserved for the free R-value calculation. Structure analysis,superposition and figure generation were done using PyMOL. (Soumana, etal. ACS Chem. Biol. 2016, 11, 900-909; Otwinowski, et al. MethodsEnzymol. 1997, 276, 307-326; McCoy, et al. J. Appl. Crystallogr. 2007,40, 658-674; Emsley, et al. Acta Crystallogr. D Biol. Crystallogr. 2004,60, 2126-2132; Adams, et al. Acta Crystallogr. D Biol. Crystallogr.2010, 66, 213-221; Davis, et al. Nucl. Acids Res. 2007, 35, W375-W383;Brunger Nature 1992, 355, 472-475; PyMOL: The PyMOL Molecular GraphicsSystem, Version 1.8, Schrödinger, LLC.)

Molecular Modeling

Molecular modeling was carried out using MacroModel (Schrödinger, LLC,New York, N.Y.). Briefly, inhibitors were modeled into the active siteof WT1a and A156T proteases using the 5172mcPIP3-WT1a co-complexstructure (PDB ID: 5EPN and 5EPY). Structures were prepared using theProtein Preparation tool in Maestro 11. 2D chemical structures weremodified with the appropriate changes using the Build tool in Maestro.Once modeled, molecular energy minimizations were performed for eachinhibitor-protease complex using the PRCG method with 2500 maximumiterations and 0.05 gradient convergence threshold. PDB files of modeledcomplexes were generated in Maestro for structural analysis. (Soumana,et al. ACS Chem. Biol. 2016, 11, 900-909; Otwinowski, et al. MethodsEnzymol. 1997, 276, 307-326)

Part 2. Macrocycle Compounds with Modifications at the P4-P5

Modifications to the scaffold of parent compound were made at the P4-P5positions to utilize unexploited space in the SE. Hydrophobic moietiesat the P4 position were used to mimic substrate interactions, as HCVsubstrates across genotypes have hydrophobic residues at this position.The objective was to extend toward the S4 substrate-binding pocket andleverage specific interactions common to substrates including backbonehydrogen bonds to residues in this binding groove. Two generalapproaches were used to sample the chemical space in this region of theSE by synthesizing a set of 9 inhibitors with either a modifiedcarbamate linked P4 capping (P4-cap inhibitors) or a modified P4 aminoacid with a small P5 capping group (P4-P5-cap inhibitors) (FIG. 7 ).

Designed Compounds Inhibit Wildtype Protease

The enzyme inhibition constants (K_(i) values) of the designedinhibitors were determined against wildtype protease and the D168A drugresistant variant. All 9 inhibitors were potent against wildtypeprotease with K_(i) values ranging from 1.13-29.5 nM (FIG. 8A, Table 6).Overall, P4-cap inhibitors (P4-1, P4-2 and P4-3) were more potent thanP4-P5-cap inhibitors that had a modified P4 amino acid and small P5capping group. P4-P5-1, an inhibitor with a t-butyl P4 moiety and smallcarbamate-linked P5 methoxy capping group, exhibited reduced potencyagainst wildtype protease (K_(i)=29.5 nM) relative to parent compound(K_(i)=3.6 nM). To test the effect of the capping group, P4-P5-2 wasdesigned, which is identical to P4-P5-1 except for the N-acetyl cappinggroup. Both P4-P5-1 and P4-P5-2 showed similar activity against wildtypeprotease. This trend was also observed with P4-P5-3 and P4-P5-4, two P4isopropyl inhibitors that differ only at the P5 position, suggestingthat the capping change tested here does not significantly affectinhibitor potency.

The P4-cap inhibitors overall had improved potency against wildtypeprotease relative to both P4-P5-cap inhibitors and the parent compound.The K_(i) values of these compounds ranged from 1.13-2.56 nM. P4-2 was3-fold more potent than the parent compound and only 5-fold less potentthan grazoprevir. While no inhibitor exhibited sub-nanomolar activityagainst wildtype protease as the FDA-approved P2-P4 macrocyclicgrazoprevir (K_(i)=0.21 nM), the P4-cap of inhibitors was modified withincrease in considerable potency. Thus, modification at the P4 positionusing a SE-guided approach yielded inhibitors with improved potencyrelative to the parent compound.

SE-Guided Design Improved Resistance Profile Against the D168A Variant

To understand if the substrate envelope as a constraint in inhibitordesign results in compounds that are less susceptible to resistance, thePIs were tested against the pivotal D168A variant. All PIs tested lostconsiderable activity against the D168A variant including grazoprevir,as has previously been reported. P4-P5-cap inhibitors were less potentagainst the D168A variant than the P4-cap inhibitors, similar towildtype protease. All P4-cap inhibitors had improved activity againstthe D168A variant (K_(i) range: 16-39 nM) relative to the parentcompound (K_(i)=52 nM). Remarkably, compound P4-3 with amethylcyclopentyl capping group exhibited 3-fold better potency againstthe D168A variant compared to the FDA-approved grazoprevir (K_(i)=16 and49 nM, respectively).

While all PIs showed reduced potency against the D168A variant relativeto WT protease in the enzyme inhibition assay, the fold losses were muchsmaller for all 9 designed inhibitors (FIG. 8B). Grazoprevir is highlysusceptible to the D168A variant exhibiting over a 230-fold reduction inpotency. All inhibitors designed to fit within and extend into thesubstrate envelope exhibited between 9- to 32-fold reductions inpotency, much smaller than observed for grazoprevir. Thus SE-guideddesign yielded flatter resistance profiles, demonstrating that thisstrategy can produce compounds with low nanomolar potency and reducedsusceptibility to drug resistance.

Structure Determination of Protease-Inhibitor Complexes

To understand the molecular basis for the observed resistance profilesof the inhibitors as well as to determine if the inhibitors fit withinthe substrate envelope as designed, crystal structures of selectinhibitors bound to wildtype and D168A proteases were determined (Table7). A total of 7 new crystal structures with resolutions ranging from1.6-1.9 Å were determined for this study. Five crystal structures ofP4-1, P4-2, P4-3, P4-P5-1 and P4-P5-2 were determined in complex withwildtype protease. Crystallization efforts with drug resistant variantD168A were successful with inhibitors P4-1 and P4-P5-2. All structureswere analyzed in comparison with previously determined crystalstructures of the parent compound (PDB ID: 5VOJ for wildtype) andgrazoprevir (PDB IDs: 3SUD for wildtype and 3SUF for D168A,respectively).

The binding mode of all of the designed inhibitors was very similar tothe parent compound and grazoprevir. The P2 quinoxaline maintained thet-t stacking interaction with catalytic His57 residue irrespective ofmodifications at the P4 and P5 positions as expected (FIG. 9 ). In fact,changes in the binding mode occurred only at the positions that weremodified, with the P3-P1′ positions of the ligand relatively unchanged.In all structures, inhibitors formed conserved hydrogen bonds withbackbone atoms in the protease including: (1) P1 amide nitrogen with thebackbone carbonyl of Arg155, (2) P3 amide nitrogen with the backbonecarbonyl of Ala157, (3) P3 cabonyl with the backbone nitrogen of Ala157and 4) the P1′ acylsulfonamide moiety with backbone atoms of residues137-139 in the oxyanion hole. Additionally, the Na nitrogen of His57made a hydrogen bond with the sulfonamide nitrogen in all inhibitorcomplexes. Differences in hydrogen bonding were observed in the S4pocket where modifications to the inhibitor were made.

Designed Inhibitors Fit within the Substrate Envelope and GainSubstrate-Like Interactions

Grazoprevir, although potent, protrudes from the substrate envelopemaking this inhibitor highly susceptible to drug resistance mutationsespecially at Ala156 and Asp168 due to the positioning of the P2-P4macrocycle and P4 moiety (FIG. 9A). Modification of the macrocyclelocation and the P2 position led to the parent compound, which fitsbetter in the substrate envelope (FIG. 9B). The crystal structures ofparent compound bound to wildtype protease and the additional 5inhibitor-wildtype protease structures superimpose extremely well.Moreover, the designed inhibitors fit within the substrate envelope,utilizing unexplored space and leveraging substrate-like contacts (FIG.9C, 3D). Thus, crystal structures confirm that inhibitors fit within thesubstrate envelope as they were designed.

Crystal structures of P4-P5-cap inhibitors bound to wildtype proteaserevealed that the carbonyl group of the P5 cap gains hydrogen bonds withthe backbone nitrogen and side chain of Ser159 (FIG. 10 ). Thisinteraction is reminiscent of the protease-substrate complexes as thisbackbone hydrogen bond to Ser159 is conserved in all structures of boundsubstrates. Both P4-P5-1 and P5-P4-2, with either an N-acetyl ormethoxycarbonyl P5 capping group, had the same additional hydrogen bondsto the backbone and side chain of Ser159 (FIGS. 10B and C). This is inagreement with the biochemical data as both inhibitors had similarpotency against wildtype protease. Thus, P4-P5-1 and P4-P5-2 bind verysimilarly to viral substrates and gain substrate-like interactions withthe protease. Although these inhibitors are not as potent as parentcompound, they demonstrate that the substrate envelope can be utilizedto design inhibitors that mimic substrate binding.

P4-P5-Cap Inhibitors Lose a Hydrogen Bond Due to D168A

To investigate the molecular basis of reduced potency for the P4-P5-capmodified inhibitors against the D168A resistant variant, crystalstructures of P4-P5-2 bound to wildtype protease and the mutant proteasewere comparatively analyzed. Similar to grazoprevir, loss in potency islikely due to disruption of the electrostatic network involving Arg155as a result of the D168A substitution (FIG. 11A-D) (16). The overallstructure of P4-P5-2 bound to the D168A is very similar to thisinhibitor bound to wildtype protease. However, a major change occurs atresidue Ser59. This residue adopts an altered side chain conformationwhere the hydroxyl group is pointed away from the inhibitor (FIG. 10B,D). As a result, the hydrogen bond of P4-P5-2 with the Ser159 side chainthat is present in the wildtype structure is lost. It is likely thatthis mechanism for reduced potency against D168A variant is the same forall inhibitors that bind similar to P4-P5-2, including P4-P5-1 and otherP4-P5-cap inhibitors.

Hydrogen Bonds within the S4 Pocket can Stabilize the Mutated ActiveSite in D168A Protease

The capping in P4-1 consists of a trifluoro-2,2-dimethylpropane moietythat can form hydrogen bonds to coordinate water molecules or furtherstabilize protease-inhibitor interactions. The crystal structure of thisinhibitor bound to wildtype protease revealed an extensive hydrogen bondnetwork around the S4 pocket including the conserved hydrogen bondbetween Arg155 and Asp168 (FIG. 11E). Additionally, there iswater-bridge between the ether oxygen of the carbamate group andbackbone nitrogen of Ser59 mimicking substrate-protease interactions(FIG. 10A). Unlike P4-P5-2, however, there is no side-chain hydrogenbond to Ser159 that is lost due to D168A mutation. Thetrifluoro-2,2-dimethylpropane moiety of P4-1 can make a hydrogen bondwith the side chain of Arg123, an additional interaction that is notpresent in the parent compound or grazoprevir. Thus, the addition ofthis electronegative P4 capping group allows for enhanced interactionwith the S4 pocket of the protease.

Unlike the P4-P5-cap inhibitors, the hydrogen bond network wasessentially unaltered for P4-1 in D168A relative to wildtype protease.The P4 capping group of P4-1 adopted two alternate conformations in theactive site when bound to D168A protease. One conformation (FIG. 11F)was stabilized by a water-bridge hydrogen bond between the fluoro groupand NH1 hydrogen of Arg155. The other conformation of P4-1 retained thefluoro-mediated hydrogen bond with Arg123 present in the wildtypeprotease structure. Although the potency of this inhibitor is reducedagainst the D168A variant, this inhibitor likely maintains potencybetter than the parent compound and grazoprevir thanks to the adaptableP4 capping group capable of conserving the hydrogen bond network.

Enhanced Packing Inside the S4 Pocket Increases Potency Against D168A

To assess the molecular details of inhibitor packing at the S4 pocket,van der Waals (vdW) contact energies were calculated for eachprotease-inhibitor structure. Total vdW energies ranged from −90 to −87kcal/mol. Most designed inhibitors had enhanced vdW contacts with theprotease relative to parent compound and grazoprevir (total vdW=−85 and−88 respectively). While the overall vdW profiles of each inhibitorclass (P4 vs P4-P5-cap) were relatively the same in the areas of theinhibitor scaffold that are common (P1′-P3), most changes occurred atthe S4 subsite (FIG. 12 ). Inhibitors P4-P5-1 and P4-P5-2, which arelarger in size than the P4-cap inhibitors, had between a 1-3 kcal/molincrease in vdW contact energy relative to the parent compound withAla157, Val158 and Ser159 when bound to wildtype protease (FIG. 12B).However, these P4-P5-cap inhibitors had not gained any interactions withAsp168, which is located deeper inside the S4 pocket. This indicatesthat P4-P5-cap inhibitors override the pocket rather than extending intothe pocket.

This is not the case for the P4-cap inhibitors with hydrophobic cappinggroups. Relative to the parent compound, P4-2 and P4-3 had increasedhydrophobic contacts with the hydrocarbon portions of the Arg123 andAsp168 side chains (FIG. 12B). The cyclic capping groups in thesecompounds extended inside the S4 pocket. Therefore P4-2 and P4-3actually fit better and fill in the S4 pocket, unlike the P4-P5-capinhibitors that override the pocket similar to grazoprevir. The P4cyclopropyl capping group of grazoprevir and the t-butyl P4 moiety ofP4-P5-2 are positioned over the S4 pocket, not optimally filling andthus potentially causing a frustrated pocket. In contrast, P4-2 and P4-3with hydrophobic cyclic rings pack well against the aliphatic portion ofthe Arg155 and Asp168 side chains and also interact with the nonpolarresidue Ala156 (FIG. 13 ). Thus, this enhanced packing of the P4 pocketbetter avoids a frustrated pocket that can destabilize inhibitor bindingand cause susceptibility to D168A mutation, improving the potency ofP4-cap inhibitors.

Experimental Inhibitor Synthesis

Grazoprevir, parent compound and substrate envelope designed analogswere synthesized in-house using previously reported methods (Scheme 4).Grazoprevir was prepared following a reported synthetic method. Theparent compound and analogs were synthesized using the convergentreaction sequence.

Expression and Purification o f NS3 4A Constructs

The HCV GT1a NS3/4A protease gene described in the Bristol Myers Squibbpatent was synthesized by GenScript and cloned into a PET28a expressionvector (34). Cys159 was mutated to a serine residue to prevent disulfidebond formation and facilitate crystallization. The D168A gene wasengineered using the site-directed mutagenesis protocol from Stratagene.Protein expression and purification were carried out as previouslydescribed (16). Briefly, transformed Escherichia coli BL21(DE3) cellswere grown in TB media containing 30 μg/mL of kanamycin antibiotic at37° C. After reaching an OD₆₀₀ of 0.7, cultures were induced with 1 mMIPTG and harvested after 3 h of expression. Cells were pelleted bycentrifugation, resuspended in resuspension buffer (RB) [50 mM phosphatebuffer, 500 mM NaCl, 10% glycerol, 2 mM R-ME, pH 7.5] and frozen at −80°C. for storage.

Cell pellets were thawed and lysed via cell disruptor (MicrofluidicsInc.) two times to ensure sufficient DNA shearing. Lysate wascentrifuged at 19,000 rpm, for 25 min at 4° C. The soluble fraction wasapplied to a nickel column (Qiagen) pre-equilibrated with RB. The beadsand soluble fraction were incubated at 4° C. for 1.5 h and the lysatewas allowed to flow through. Beads were washed with RB supplemented with20 mM imidazole and eluted with RB supplemented with 200 mM imidazole.The eluent was dialyzed overnight (MWCO 10 kD) to remove the imidazole,and the His-tag was simultaneously removed with thrombin treatment. Theeluate was judged >90% pure by polyacrylamide gel electrophoresis,concentrated, flash frozen, and stored at −80° C.

Correction for the Inner Filter Effect

The inner filter effect (IFE) for the NS3/4A protease substrate wasdetermined using a previously described method. Briefly, fluorescenceend-point readings were taken for substrate concentrations between 0 μMand 20 μM. Afterward, free 5-FAM fluorophore was added to a finalconcentration of 25 μM to each substrate concentration and a secondround of fluorescence end-point readings was taken. The fluorescence offree 5-FAM was determined by subtracting the first fluorescence endpoint reading from the second round of readings. IFE corrections werethen calculated by dividing the free 5-FAM florescence at each substrateconcentration by the free 5-FAM florescence at zero substrate.

Determination of Michaelis-Menten (K) Constant

K_(m) constants for GT1 and D168A protease were previously determined(26). Briefly, a 20 μM concentration of substrate[Ac-DE-Dap(QXL520)-EE-Abu-γ-[COO]AS-C(5-FAMsp)-NH2](AnaSpec) wasserially diluted into assay buffer [50 mM Tris, 5% glycerol, 10 mM DTT,0.6 mM LDAO, and 4% dimethyl sulfoxide] and proteolysis was initiated byrapid injection of 10 μL protease (final concentration 20 nM) in areaction volume of 60 μL. The fluorescence output from the substratecleavage product was measured kinetically using an EnVision plate reader(Perkin-Elmer) with excitation wavelength at 485 nm and emission at 530nm. Inner filter effect corrections were applied to the initialvelocities (V_(o)) at each substrate concentration. V_(o) versussubstrate concentration graphs were globally fit to the Michaelis-Mentenequation to obtain the K_(m) value.

Enzyme Inhibition Assays

For each assay, 2 nM of NS3/4A protease (GT1a and D168A) waspre-incubated at room temperature for 1 h with increasing concentrationof inhibitors in assay buffer (50 mM Tris, 5% glycerol, 10 mM DTT, 0.6mM LDAO, and 4% dimethyl sulfoxide, pH 7.5). Inhibition assays wereperformed in non-binding surface 96-well black half-area plates(Corning) in a reaction volume of 60 μL. The proteolytic reaction wasinitiated by the injection of 5 μL of HCV NS3/4A protease substrate(AnaSpec), to a final concentration of 200 nM and kinetically monitoredusing a Perkin Elmer EnVision plate reader (excitation at 485 nm,emission at 530 nm). Three independent data sets were collected for eachinhibitor with each protease construct. Each inhibitor titrationincluded at least 12 inhibitor concentration points, which were globallyfit to the Morrison equation to obtain the K_(i) value.

Crystallization and Structure Determination

Protein expression and purification were carried out as previouslydescribed (16). Briefly, the Ni-NTA purified WT1a protein was thawed,concentrated to 3 mg/mL, and loaded on a HiLoad Superdex75 16/60 columnequilibrated with gel filtration buffer (25 mM MES, 500 mM NaCl, 10%glycerol, and 2 mM DTT, pH 6.5). The protease fractions were pooled andconcentrated to 25 mg/mL with an Amicon Ultra-15 10 kDa filter unit(Millipore). The concentrated samples were incubated for 1 h with 3:1molar excess of inhibitor. Diffraction-quality crystals were obtainedovernight by mixing equal volumes of concentrated protein solution withprecipitant solution (20-26% PEG-3350, 0.1 M sodium MES buffer, 4%ammonium sulfate, pH 6.5) at RT or 15° C. in 24-well VDX hanging droptrays. Crystals were harvested and data was collected at 100 K.Cryogenic conditions contained the precipitant solution supplementedwith 15% glycerol or ethylene glycol.

X-ray diffraction data were collected in-house using the Rigaku X-raysystem with a Saturn 944 detector. All datasets were processed usingHKL-3000. Structures were solved by molecular replacement using PHASER.Model building and refinement were performed using Coot and PHENIX,respectively. The final structures were evaluated with MolProbity priorto deposition in the PDB. To limit the possibility of model biasthroughout the refinement process, 5% of the data were reserved for thefree R-value calculation. Structure analysis, superposition and figuregeneration were done using PyMOL. X-ray data collection andcrystallographic refinement statistics are presented in Table 6.

Construction of HCV Substrate Envelope

The HCV substrate envelope was computed using a method previouslydescribed (16). The HCV viral substrates representing the productcomplex 3-4A (residues 626-631 of full-length HCV PDB ID: 1CU1), 4B/5A(chain D, PDB ID: 3M5N) and 5A/5B (chain A, PDB ID: 3M50) were used toconstruct the envelope. All structure were aligned in PyMOL using the Caatoms of protease residues 137-139 and 154-160. Following superpositionof all structures, Gaussian object maps at a contour of 0.5 weregenerated for each cleavage product in PyMOL. Three consensus maps weregenerated representing the minimum volume occupied by any 2 viralsubstrates. The four consensus maps were summed together to generate thefinal substrate envelope representing the shared van der Waals volume ofthe viral substrates.

TABLE 6 Inhibitory activity against GT1a HCV NS3/4A and D168A proteaseswith fold changes with respect to GT1a wild-type Ki (nM) (Fold Change)Inhibitor GT1a WT D168A P4-P5-1 29.5 ± 1.9  201.0 ± 15.0  (8) P4-P5-223.9 ± 1.7  215.0 ± 16.0  (9) P4-P5-3 13.0 ± 0.8  102.0 ± 6.8   (8)P4-P5-4 11.1 ± 0.5  141.0 ± 18.0 (13) P4-P5-5 3.54 ± 0.13 31.6 ± 2.1 (9) P4-P5-6 7.10 ± 0.24  81.0 ± 11.0 (11) P4-1 2.56 ± 0.44 39.0 ± 2.9(15) P4-2 1.13 ± 0.22 36.0 ± 1.8 (32) P4-3 1.78 ± 0.30 16.0 ± 1.2

TABLE 7 X-ray data collection and crystallographic refinement statisticsWT- WT- WT- WT- WT- D168A- D168A- P4-P5-1 P4-P4-2 P4-1 P4-2 P4-3 P4-P5-2P4-1 PDB ID: 6DIQ 6DIR 6DIS 6DIT 6DIU 6DIV 6DIW Resolution 1.58 Å 1.75 Å1.92 Å 1.79 Å 1.87 Å 1.83 Å 1.80 Å Space group P2₁2₁2₁ P2₁2₁2₁ P2₁2₁2₁P2₁2₁2₁ P2₁2₁2₁ P2₁2₁2₁ P2₁2₁2₁ Molecules in AU^(a) 1 1 1 1 1 1 1 Celldimensions: a (Å) 55.5 55.1 55.6 55.3 55.1 55.5 55.7 b (Å) 58.5 59.858.6 58.6 59.6 58.7 58.6 c (Å) 59.9 58.5 60.0 59.8 58.5 60.0 60.1 β (°)90 90 90 90 90 90 90 Completeness (%) 91.3 97.0 96.7 98.1 97.4 98.1 92.6Total reflections 250177 119548 106822 118729 110776 115996 120162Unique reflections 25037 19508 14999 18610 16126 17556 17476 Average I/σ7.9 8.8 19.8 14.5 12.7 12.8 6.3 Redundancy 10 6.1 7.1 6.4 6.9 6.6 6.9R_(sym) (%)^(b) 5.7 (15.2) 4.3 (18.3) 10.6 (45.8) 7.1 (28.4) 6.3 (19.6)7.0 (21.6) 3.9 (11.7) RMSD^(c) in: Bond lengths (Å) 0.007 0.009 0.010.004 0.02 0.006 0.01 Bond angles (°) 1.0 1.3 1.0 0.8 0.6 1.1 1.5R_(factor) (%)^(d) 15.1 14.6 18.7 18.2 18.3 16.1 13.8 R_(free) (%)^(e)18.3 19.3 22.7 22.9 23.3 19.4 18.0 (9) Parent Compound 3.60 ± 0.44 52.0± 2.4 (14) Grazoprevir 0.21 ± 0.03 49.1 ± 1.6 (234) ^(a)AU, asymmetricunit. ^(b)R_(sym) = Σ | I − <I>|/Σ I, where I = observed intensity, <I>= average intensity over symmetry equivalent; values in parentheses arefor the highest resolution shell. ^(c)RMSD, root mean square deviation.^(d)R_(factor) = Σ ∥ F_(o)| − |F_(c)∥/Σ|F_(o)|. ^(e)R_(free) wascalculated from 5% of reflections, chosen randomly, which were omittedfrom the refinement process.

All reactions were performed in oven-dried round bottomed flasks fittedwith rubber septa under argon atmosphere, unless otherwise noted. Allreagents and solvents, including anhydrous solvents, were purchased fromcommercial sources and used as received. Flash column chromatography wasperformed on an ISCO CombiFlash instrument using RediSep Gold columns.Thin-layer chromatography (TLC) was performed using silica gel (60F-254) coated aluminum plates (EMD Millipore), and spots were visualizedby exposure to ultraviolet light (UV), exposure to iodine adsorbed onsilica gel, and/or exposure to an acidic solution of p-anisaldehyde(anisaldehyde) followed by brief heating. ¹H NMR and ¹³C NMR spectrawere acquired on a Bruker Avance III HD 500 MHz NMR instrument. Chemicalshifts are reported in ppm (6 scale) with the residual solvent signalused as reference and coupling constant (J) values are reported in hertz(Hz). Data are presented as follows: chemical shift, multiplicity(s=singlet, d=doublet, dd=doublet of doublet, t=triplet, q=quartet,m=multiplet, br s=broad singlet), coupling constant in Hz, andintegration. High-resolution mass spectra (HRMS) were recorded on aThermo Scientific Orbitrap Velos Pro mass spectrometer coupled with aThermo Scientific Accela 1250 UPLC and an autosampler using electrosprayionization (ESI) in the positive mode.

Scheme 4. Synthesis of HCV NS3/4A Protease Inhibitors

-   -   Reagents ad Conditions: (a) Cs₂CO₃, NMP, 55° C., 6 h; (b) 4 N        HCl in dioxane, CH₂Cl₂, RT, 3 h; (c) HATU, DIEA, DMF, RT, 4        h; (d) LiOH.H₂O, THF, H₂O, RT, 24 h; (e) HATU, DIEA, DMF, RT, 2        h; (f) Zhan 1b catalyst, 1,2-DCE, 70° C., 6 h; (g) 4 N HCl,        dioxane, RT, 3 h; (h) alcohol-(4-nitrophenyl) carbonate, DIEA,        CH₃CN, RT, 36 h; (1)N-protected amino acid, HATU, DIEA, DMF, RT,        4 h.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(3)

A solution of 7-methoxy-3-methylquinoxalin-2(1H)-one 1 (6.2 g, 32.6mmol) in anhydrous NMP (100 mL) was treated with Cs₂CO₃ (16.0 g, 49.0mmol). After stirring the reaction mixture at room temperature for 15min, activated cis-hydroxyproline derivative 2 (14.0 g, 30.2 mmol) wasadded in one portion. The reaction mixture was heated to 55° C., stirredfor 4 h, and then another portion of activated cis-hydroxyproline 2 (1.0g, 2.15 mmol) was added. The resulting reaction mixture was stirred at55° C. for additional 2 h, cooled to room temperature, quenched withaqueous 1 N HCl solution (250 mL), and extracted with EtOAc (400 mL).The organic fraction was washed successively with saturated aqueousNaHCO₃ and NaCl (250 mL each), dried (Na₂SO₄), filtered, and evaporatedunder reduced pressure. The residue was purified by flash columnchromatography (RediSep Gold column, 2×80 g, gradient elution with 0-60%EtOAc/hexanes) to provide 3 (10.0 g, 74%) as a white foamy solid. ¹H NMR(500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.80 (d, J=9.0Hz, 1H), 7.17 (dd, J=9.0, 3.0 Hz, 1H), 7.11 (d, J=2.5 Hz, 1H), 5.71 (brs, 1H), 4.48 (t, J=8.0 Hz, 1H), 3.99-3.91 (m, 4H), 3.87 (d, J=12.5 Hz,1H), 3.78 (s, 3H), 2.67-2.58 (m, 1H), 2.56 (s, 3H), 2.43-2.37 (m, 1H),1.43 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 173.36, 160.24, 155.51,153.81, 144.60, 141.04, 134.22, 128.95, 118.63, 105.95, 80.54, 73.59,58.20, 55.68, 52.48, 52.20, 36.70, 28.26, 19.93 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₁H₂₈N₃O₆, 418.1973; found 418.1976.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)non-8-enoyl)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(6)

A solution of ester 3 (10.0 g, 24.0 mmol) in anhydrous CH₂Cl₂ (50 mL)was treated with a solution of 4 N HCl in 1,4-dioxane (100 mL). Afterstirring the reaction mixture at room temperature for 3 h, solvents wereevaporated under reduced pressure, and the residue was dried under highvacuum. The pale-yellow solid was triturated with diethyl ether (3×25mL) and dried under high vacuum to yield the amine salt 4 (8.5 g, 100%)as an off-white powder. A mixture of amine salt 4 (8.5 g, 24.0 mmol) and(S)-2-((tert-butoxycarbonyl)amino)non-8-enoic acid 5 (6.70 g, 24.7 mmol)in anhydrous DMF (110 mL) was treated with DIEA (19.2 mL, 110 mmol) andHATU (14.1 g, 37.1 mmol). The resulting reaction mixture was stirred atroom temperature for 4 h, then diluted with EtOAc (500 mL), and washedsuccessively with aqueous 0.5 N HCl, saturated aqueous NaHCO₃, andsaturated aqueous NaCl (300 mL each). The organic portion was dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash column chromatography (RediSep Gold column, 2×80g, gradient elution with 0-60% EtOAc/hexanes) to provide 6 (10.9 g, 80%)as a white foamy solid. ¹H NMR (500 MHz, CDCl₃) (mixture of rotamers,major rotamer) δ 7.81 (d, J=9.0 Hz, 1H), 7.18 (dd, J=9.0, 2.5 Hz, 1H),7.12 (d, J=2.5 Hz, 1H), 5.84-5.75 (m, 2H), 5.21 (d, J=8.5 Hz, 1H),5.01-4.92 (m, 2H), 4.75 (t, J=8.0 Hz, 1H), 4.38 (q, J=7.5 Hz, 1H), 4.18(d, J=11.5 Hz, 1H), 4.06 (dd, J=12.0, 4.5 Hz, 1H), 3.94 (s, 3H), 3.77(s, 3H), 2.69-2.64 (m, 1H), 2.54 (s, 3H), 2.41-2.35 (m, 1H), 2.04 (appq, J=7.0 Hz, 2H), 1.80-1.75 (m, 1H), 1.63-1.55 (m, 1H), 1.46-1.24 (m,15H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 172.13, 171.78, 160.27, 155.40,155.27, 144.62, 140.89, 138.96, 134.39, 129.03, 118.73, 114.35, 105.99,79.61, 74.30, 57.97, 55.66, 52.67, 52.43, 51.83, 34.94, 33.65, 32.66,28.91, 28.74, 28.25, 24.68, 19.87 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₀H₄₃N₄O₇, 571.3126; found 571.3128.

tert-Butyl((S)-1-((2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-1-oxonon-8-en-2-yl)carbamate(9)

A solution of ester 6 (6.0 g, 10.5 mmol) in THF-H₂O mixture (1:1, 150mL) was treated with LiOH.H₂O (1.55 g, 36.9 mmol). The resultingreaction mixture was stirred at room temperature for 24 h. The reactionmixture was cooled to ˜5° C., acidified to a pH of 2.0 by slow additionof aqueous 0.25 N HCl (˜200 mL), and extracted with EtOAc (2×400 mL).The organic portions were washed separately with saturated aqueous NaCl(200 ml), dried (Na₂SO₄), filtered, and evaporated under reducedpressure. The gummy residue was dissolved in CHCl₃ (50 mL), concentratedunder reduced pressure, and the residue was dried under high vacuumovernight to yield the acid 7 (5.80 g, 99%) as a white solid.

A mixture of acid 7 (5.57 g, 10.0 mmol) and amine salt 8 (3.10 g, 11.0mmol) in anhydrous DMF (100 mL) was treated with DIEA (6.70 mL, 40.5mmol) and HATU (5.70 g, 15.0 mmol). The resulting reaction mixture wasstirred at room temperature for 2.5 h, then diluted with EtOAc (400 mL)and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (250 mL each). The organic portionwas dried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash column chromatography (RediSep Goldcolumn, 2×80 g, gradient elution with 20-90% EtOAc/hexanes) to providethe bis-olefin compound 9 (6.50 g, 83%) as a white solid. ¹H NMR (400MHz, CDCl₃) δ 10.02 (s, 1H), 7.81 (d, J=8.8 Hz, 1H), 7.18 (dd, J=8.8,2.8 Hz, 1H), 7.13 (d, J=2.8 Hz, 1H), 7.11 (s, 1H), 5.88 (br s, 1H),5.82-5.72 (m, 2H), 5.42 (d, J=9.2 Hz, 1H), 5.26 (d, J=17.2 Hz, 1H), 5.14(d, J=11.6 Hz, 1H), 5.00-4.90 (m, 2H), 4.50 (t, J=8.4 Hz, 1H), 4.39-4.33(m, 1H), 4.18 (d, J=11.6 Hz, 1H), 4.02 (dd, J=11.6, 4.0 Hz, 1H), 3.93(s, 3H), 2.58-2.50 (m, 5H), 2.10 (q, J=8.4 Hz, 1H), 2.05-1.98 (m, 3H),1.73-1.58 (m, 4H), 1.49 (s, 3H), 1.44-1.24 (m, 16H), 0.92-0.86 (m, 1H),0.84-0.78 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 173.65, 172.52, 167.55,160.31, 155.70, 155.16, 144.41, 140.87, 138.83, 134.33, 132.61, 128.96,118.87, 118.54, 114.41, 105.96, 79.73, 74.59, 60.30, 55.67, 53.15,52.37, 41.73, 36.56, 35.16, 34.25, 33.62, 32.24, 28.71, 28.67, 28.26,25.31, 23.42, 19.84, 18.37, 14.27, 13.26 ppm; HRMS (ESI) m/z: [M+H]⁺calcd for C₃₉H₅₅N₆O₉S, 783.3746; found 783.3734.

tert-Butyl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(10)

A degassed solution of bis-olefin 9 (6.20 g, 7.92 mmol) in 1,2-DCE (1600mL) was heated to 50° C. under argon, then Zhan 1b catalyst (0.50 g,0.68 mmol) was added in two portions over 10 min. The resulting reactionmixture was heated to 70° C. and stirred for 6 h. The reaction mixturewas cooled to room temperature and solvents were evaporated underreduced pressure. The residue was purified by flash columnchromatography (RediSep Gold column, 2×80 g, gradient elution with20-90% EtOAc/hexanes) to yield the P1-P3 macrocyclic product 10 (4.20 g,70%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.16 (s, 1H),7.82 (d, J=9.2 Hz, 1H), 7.19-7.16 (m, 2H), 6.92 (s, 1H), 5.88 (br s,1H), 5.69 (q, J=9.2 Hz, 1H), 5.12 (d, J=7.6 Hz, 1H), 4.99 (t, J=8.8 Hz,1H), 4.61 (t, J=8.0 Hz, 1H), 4.51 (d, J=11.2 Hz, 1H), 4.28-4.22 (m, 1H),4.03 (dd, J=11.2, 4.0 Hz, 1H), 3.95 (s, 3H), 2.70-2.50 (m, 6H), 2.31 (q,J=8.8 Hz, 1H), 1.92-1.66 (m, 4H), 1.60-1.20 (m, 21H), 0.85-0.78 (m, 2H)ppm; ¹³C NMR (100 MHz, CDCl₃) δ 177.16, 173.33, 166.94, 160.33, 155.32,155.04, 144.46, 141.03, 134.20, 136.25, 128.66, 124.89, 118.93, 105.98,79.85, 74.88, 59.46, 55.72, 53.08, 51.97, 44.73, 36.43, 34.61, 32.72,29.65, 28.15, 27.06, 26.07, 22.21, 20.96, 19.71, 18.17, 14.51, 12.51ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₇H₅₁N₆O₉S, 755.3433; found755.3404. Anal. HPLC: t_(R) 13.57 min, purity 99%.

(2R,6S,13aS,14aR,16aS,Z)-6-Amino-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-N-((1-methylcyclopropyl)sulfonyl)-5,16-dioxo-1,2,3,6,7,8,9,10,11,13a,14,15,16,16a-tetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecine-14a(5H)-carboxamidehydrochloride (11)

A solution of compound 10 (3.25 g, 4.31 mmol) in anhydrous CH₂CL₂ (15mL) was treated with a solution of 4 N HCl in 1,4-dioxane (50 mL). Thereaction mixture was stirred at room temperature for 3 h, concentratedunder reduced pressure, and the residue was dried under high vacuum. Theresidue was triturated with diethyl ether (40 mL), and the solid wasfiltered, washed with Et₂O (2×15 mL), and dried under high vacuum toyield the amine salt 11 (2.90 g, 98%) as an off-white solid.

1,1,1-trifluoro-2-methylpropan-2-yl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(P4-1)

A solution of the amine salt 11 (0.25 g, 0.36 mmol) in anhydrous CH₃CN(10 mL) was treated with DIEA (0.45 mL, 2.58 mmol) and 4-nitrophenyl(1,1,1-trifluoro-2-methylpropan-2-yl) carbonate (0.110 g, 0.37 mmol).The resulting reaction mixture was stirred at room temperature for 24 h,then concentrated under reduced pressure and dried under high vacuum.The residue was purified by flash column chromatography (RediSep Goldcolumn, 24 g, gradient elution with 10-90% EtOAc/hexanes) to provide thetarget compound P4-1 (0.28 g, 96%) as a white solid. ¹H NMR (500 MHz,CDCl₃) δ 10.16 (s, 1H), 7.79 (d, J=10.0 Hz, 1H), 7.19-7.16 (m, 2H), 7.03(s, 1H), 5.87 (br s, 1H), 5.72-5.64 (m, 2H), 4.97 (t, J=9.5 Hz, 1H),4.61 (t, J=8.0 Hz, 1H), 4.48 (d, J=11.5 Hz, 1H), 4.26-4.22 (m, 1H), 4.02(dd, J=11.5, 4.0 Hz, 1H), 3.94 (s, 3H), 2.66-2.63 (m, 2H), 2.59-2.50 (m,4H), 2.30 (q, J=9.0 Hz, 1H), 1.89-1.73 (m, 4H), 1.60-1.22 (m, 18H),0.84-0.80 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 177.28, 172.28,167.14, 160.43, 155.40, 153.35, 141.61, 141.10, 136.42, 134.39, 129.01,125.05 (q, J=281 Hz), 124.97, 118.94, 106.16, 79.78 (d, J=29.3 Hz),74.99, 59.70, 55.84, 53.27, 52.28, 44.81, 36.60, 34.82, 32.66, 29.62,27.27, 27.21, 26.28, 22.20, 20.94, 19.88, 19.49, 19.43, 18.29, 14.64,12.68 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₇H₄₈F₃N₆O₉S⁺, 809.3150;found 809.3128.

1-methylcyclopentyl((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamate(P4-3)

The same procedure was used as described above for compound P4-1. Amixture of amine salt 11 (0.25 g, 0.36 mmol) was treated with DIEA (0.45mL, 2.58 mmol) and 1-methylcyclopentyl (4-nitrophenyl) carbonate (0.098g, 0.37 mmol) to provide the target compound P4-3 (0.24 g, 85%) as awhite solid. ¹H NMR (500 MHz, CDCl₃) δ 10.13 (s, 1H), 7.79 (d, J=10.0Hz, 1H), 7.18-7.16 (m, 2H), 6.87 (s, 1H), 5.89 (br s, 1H), 5.70 (q,J=9.0 Hz, 1H), 5.12 (d, J=7.5 Hz, 1H), 5.00 (t, J=9.0 Hz, 1H), 4.61 (t,J=7.5 Hz, 1H), 4.50 (d, J=11.5 Hz, 1H), 4.28 (t, J=8.0 Hz, 1H), 4.04(dd, J=11.0, 4.0 Hz, 1H), 3.95 (s, 3H), 2.69-2.50 (m, 6H), 2.31 (q,J=8.5 Hz, 1H), 1.93-1.76 (m, 6H), 1.65-1.25 (m, 21H), 0.85-0.79 (m, 2H)ppm; ¹³C NMR (125 MHz, CDCl₃) δ 177.11, 173.33, 166.90, 160.27, 155.31,155.20, 144.50, 140.98, 136.24, 134.31, 128.89, 124.92, 118.78, 106.03,89.54, 74.79, 59.47, 55.72, 53.11, 52.03, 44.75, 39.28, 39.08, 36.47,34.61, 32.79, 29.71, 27.11, 27.06, 26.09, 24.59, 23.77, 22.26, 21.00,19.86, 18.20, 14.52, 12.57 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₉H₅₃N₆O₉S⁺, 781.3589; found 781.3570.

(2R,6S,13aS,14aR,16aS,Z)-6-((S)-2-Acetamido-3,3-dimethylbutanamido)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-N-((1-methylcyclopropyl)sulfonyl)-5,16-dioxo-1,2,3,6,7,8,9,10,11,13a,14,15,16,16a-tetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecine-14a(5H)-carboxamide(P4-P5-2)

A mixture of amine salt 11 (0.31 g, 0.45 mmol) and N-Ac-Tle-OH (0.10 g,0.58 mmol) in anhydrous DMF (8 mL) was treated with DIEA (0.60 mL, 3.50mmol) and HATU (0.35 g, 0.92 mmol). The resulting reaction mixture wasstirred at room temperature for 5 h, then diluted with EtOAc (100 mL),and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (75 mL each). The organic portion wasdried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash column chromatography (RediSep Goldcolumn, 12 g, gradient elution with 80-100% EtOAc/hexanes) to provideP4-P5-2 (0.28 g, 77%) as a white solid. ¹H NMR (500 MHz, CD₃OD) δ 7.76(d, J=9.0 Hz, 1H), 7.26 (d, J=2.5 Hz, 1H), 7.21 (dd, J=9.0, 3.0 Hz, 1H),5.95 (br s, 1H), 5.70 (q, J=8.5 Hz, 1H), 5.05 (t, J=9.0 Hz, 1H), 4.68(dd, J=9.0, 7.5 Hz, 1H), 4.63 (d, J=11.5 Hz, 1H), 4.44 (dd, J=11.5, 3.0Hz, 1H), 4.13-4.09 (m, 2H), 3.94 (s, 3H), 2.73-2.63 (m, 2H), 2.57-2.46(m, 5H), 2.00-1.93 (m, 1H), 1.91-1.83 (m, 4H), 1.72 (dd, J=8.5, 5.5 Hz,1H), 1.64-1.36 (m, 13H), 1.33-1.26 (m, 1H), 0.90-0.84 (m, 2H), 0.74 (s,9H) ppm; ¹³C NMR (125 MHz, CD₃OD) δ 179.38, 173.54, 172.91, 171.70,169.52, 162.05, 156.98, 146.05, 142.68, 136.89, 134.86, 129.27, 126.45,119.79, 107.34, 76.88, 61.43, 60.87, 56.26, 54.47, 52.16, 45.36, 37.59,36.09, 35.30, 33.27, 30.92, 28.65, 28.23, 27.87, 27.04, 23.29, 22.37,21.75, 19.91, 18.43, 14.57, 13.01 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₄₀H₅₆N₇O₉S⁺, 810.3855; found 810.3836.

(2R,6S,13aS,14aR,16aS,Z)-6-((S)-2-Acetamido-3-methylbutanamido)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-N-((1-methylcyclopropyl)sulfonyl)-5,16-dioxo-1,2,3,6,7,8,9,10,11,13a,14,15,16,16a-tetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecine-14a(5H)-carboxamide(P4-P5-4)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt 11 (0.25 g, 0.36 mmol) and N-Ac-Val-OH (0.075 g,0.47 mmol) was treated with DIEA (0.50 mL, 2.87 mmol) and HATU (0.30 g,0.79 mmol) to provide the target compound P4-P5-4 (0.30 g, 80%) as awhite solid. ¹H NMR (500 MHz, CD₃OD) δ 7.76 (d, J=9.0 Hz, 1H), 7.26 (d,J=3.0 Hz, 1H), 7.20 (dd, J=9.5, 3.0 Hz, 1H), 5.98 (br s, 1H), 5.69 (q,J=9.0 Hz, 1H), 5.05 (t, J=9.0 Hz, 1H), 4.68 (t, J=9.0 Hz, 1H), 4.60 (d,J=12.0 Hz, 1H), 4.42 (dd, J=11.5, 3.0 Hz, 1H), 4.09 (dd, J=11.5, 4.0,Hz, 1H), 4.05 (d, J=7.5 Hz, 1H), 3.93 (s, 3H), 2.72-2.62 (m, 2H),2.58-2.52 (m, 1H), 2.50 (s, 3H), 2.43 (q, J=8.5 Hz, 1H), 1.97-1.81 (m,6H), 1.72 (dd, J=8.5, 5.5 Hz, 1H), 1.64-1.29 (m, 14H), 0.90-0.84 (m,2H), 0.79 (t, J=7.5 Hz, 6H) ppm; ¹³C NMR (125 MHz, CD₃OD) δ 179.28,173.79, 173.16, 172.76, 169.47, 162.01, 157.02, 146.26, 142.65, 136.85,134.82, 129.24, 126.43, 119.75, 107.33, 76.70, 60.78, 59.49, 56.26,54.41, 52.42, 45.29, 37.59, 35.96, 33.29, 32.07, 31.00, 28.60, 28.35,27.82, 23.21, 22.37, 21.78, 19.80, 19.71, 18.68, 18.43, 14.57, 13.02ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₉H₅₄N₇O₉S⁺, 796.3698; found796.3679.

(2R,6S,13aS,14aR,16aS,Z)-6-((2S,3S)-2-acetamido-3-methylpentanamido)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-N-((1-methylcyclopropyl)sulfonyl)-5,16-dioxo-1,2,3,6,7,8,9,10,11,13a,14,15,16,16a-tetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecine-14a(5H)-carboxamide(P4-P5-6)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt AJ-63 (0.15 g, 0.22 mmol) and N-Ac-Ile-OH (0.061g, 0.35 mmol) was treated with DIEA (0.23 mL, 1.4 mmol) and HATU (0.21g, 0.55 mmol) to provide the target compound P4-P5-6 (0.10 g, 56%) as awhite solid. ¹H NMR (500 MHz, CD₃OD) δ 8.15 (d, J=7.0 Hz, 1H), 7.77-7.73(m, 2H), 7.25 (d, J=2.5 Hz, 1H), 7.20 (dd, J=9.0, 2.5 Hz, 1H), 5.98 (brs, 1H), 5.70 (q, J=8.5 Hz, 1H), 5.05 (t, J=9.0 Hz, 1H), 4.67 (t, J=8.5Hz, 1H), 4.62 (d, J=12.0 Hz, 1H), 4.44-4.40 (m, 1H), 4.11-4.05 (m, 2H),3.93 (s, 3H), 2.71-2.62 (m, 2H), 2.58-2.50 (m, 4H), 2.43 (q, J=8.5 Hz,1H), 1.99-1.84 (m, 5H), 1.73 (dd, J=8.0, 5.5 Hz, 1H), 1.64-1.25 (m,15H), 1.09-1.00 (m, 1H), 0.90-0.84 (m, 2H), 0.82 (t, J=7.5 Hz, 3H), 0.73(d, J=7.0 Hz, 3H) ppm; ¹³C NMR (125 MHz, CD₃OD) δ 179.32, 173.67,173.04, 172.90, 169.48, 162.00, 157.02, 146.25, 142.65, 136.84, 134.81,129.23, 126.43, 119.74, 107.33, 76.71, 60.75, 58.56, 56.27, 54.38,52.43, 45.31, 38.16, 37.59, 35.97, 33.21, 31.01, 28.61, 28.32, 27.81,25.96, 23.23, 22.36, 21.75, 19.80, 18.44, 15.87, 14.57, 13.01, 11.29ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₄₀H₅₆N₇O₉S⁺, 810.3855; found810.3832.

Methyl((S)-1-(((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)amino)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(P4-P5-1)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt 11 (0.25 g, 0.36 mmol) andmethoxycarbonyl-L-tert-leucine (0.093 g, 0.48 mmol) was treated withDIEA (0.50 mL, 2.87 mmol) and HATU (0.30 g, 0.79 mmol) to provide thetarget compound P4-P5-1 (0.25 g, 84%) as a white solid. ¹H NMR (500 MHz,CDCl₃) δ 10.22 (s, 1H), 8.64 (br s, 1H), 8.04 (d, J=8.5 Hz, 1H), 7.77(d, J=9.0 Hz, 1H), 7.20-7.16 (m, 2H), 5.89 (br s, 1H), 5.68 (q, J=8.5Hz, 1H), 5.48 (d, J=10.0 Hz, 1H), 4.96-4.91 (m, 2H), 4.70 (t, J=8.0 Hz,1H), 4.43 (d, J=12.0 Hz, 1H), 4.19 (dd, J=11.5, 4.0 Hz, 1H), 3.95 (s,3H), 3.86 (d, J=10.0 Hz, 1H), 3.63 (s, 3H), 2.78-2.63 (m, 3H), 2.45 (s,3H), 2.10 (q, J=8.5 Hz, 2H), 1.85-1.70 (m, 3H), 1.50-1.13 (m, 11H), 0.98(dd, J=10.4, 6.0 Hz, 1H), 0.83-0.77 (m, 2H), 0.65 (s, 9H) ppm; ¹³C NMR(125 MHz, CDCl₃) δ 176.65, 172.94, 169.36, 166.94, 160.56, 157.69,155.14, 143.75, 141.13, 136.92, 134.45, 128.99, 124.90, 119.23, 106.12,75.10, 62.27, 59.25, 55.87, 54.13, 53.24, 50.35, 44.09, 36.64, 35.40,35.10, 34.38, 28.74, 27.56, 27.50, 26.73, 26.52, 22.89, 19.92, 19.80,18.31, 14.57, 12.73 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₄₀H₅₆N₇O₁₀S⁺,826.3804; found 826.3778.

Methyl((S)-1-(((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate(P4-P5-3)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt 11 (0.25 g, 0.36 mmol) andmethoxycarbonyl-L-valine (0.085 g, 0.48 mmol) was treated with DIEA(0.50 mL, 2.87 mmol) and HATU (0.30 g, 0.79 mmol) to provide the targetcompound P4-P5-3 (0.24 g, 82%) as a white solid. ¹H NMR (500 MHz, CDCl₃)δ 10.25 (s, 1H), 8.71 (br s, 1H), 8.43 (br s, 1H), 7.80 (d, J=9.5 Hz,1H), 7.21-7.18 (m, 2H), 5.95 (br s, 1H), 5.72 (q, J=8.5 Hz, 1H), 5.48(d, J=9.5 Hz, 1H), 4.98-4.89 (m, 2H), 4.67 (t, J=8.0 Hz, 1H), 4.45 (d,J=11.5 Hz, 1H), 4.25 (dd, J=9.5, 4.5 Hz, 1H), 4.19 (dd, J=11.5, 4.0 Hz,1H), 3.95 (s, 3H), 3.64 (s, 3H), 2.80-2.65 (m, 3H), 2.43 (s, 3H), 2.21(q, J=8.5 Hz, 1H), 2.14-2.07 (m, 1H), 1.87-1.65 (m, 3H), 1.58-1.36 (m,10H), 1.31-1.17 (m, 2H), 1.01 (dd, J=9.0, 5.5 Hz, 1H), 0.82-0.77 (m,5H), 0.67 (d, J=7.0 Hz, 3H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 177.09,173.68, 170.18, 167.08, 160.67, 157.98, 155.22, 143.79, 141.16, 136.88,134.23, 128.91, 124.87, 119.39, 106.12, 75.07, 59.56, 58.46, 55.90,54.14, 53.30, 50.23, 44.37, 36.61, 35.53, 34.69, 32.78, 28.66, 27.71,27.51, 26.90, 22.39, 20.06, 19.72, 19.61, 18.35, 16.70, 14.72, 12.72ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₉H₅₄N₇O₁₀S⁺, 812.3647; found812.3624.

Methyl((S)-1-cyclopentyl-2-(((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)amino)-2-oxoethyl)carbamate(P4-P5-5)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt 11 (0.25 g, 0.36 mmol) andmethoxycarbonyl-L-cyclopentylglycine (0.096 g, 0.48 mmol) was treatedwith DIEA (0.50 mL, 2.87 mmol) and HATU (0.30 g, 0.79 mmol) to providethe target compound P4-P5-5 (0.25 g, 83%) as a white solid. ¹H NMR (500MHz, CDCl₃) δ 10.26 (s, 1H), 8.73 (br s, 1H), 8.40 (br s, 1H), 7.79 (d,J=10.0 Hz, 1H), 7.20-7.18 (m, 2H), 5.96 (br s, 1H), 5.71 (q, J=9.0 Hz,1H), 5.52 (d, J=9.5 Hz, 1H), 4.97-4.89 (m, 2H), 4.68 (t, J=8.0 Hz, 1H),4.43 (d, J=11.5 Hz, 1H), 4.37 (dd, J=9.5, 5.0 Hz, 1H), 4.21 (dd, J=11.5,4.5 Hz, 1H), 3.95 (s, 3H), 3.64 (s, 3H), 2.72-2.67 (m, 2H), 2.47 (s,3H), 2.17 (q, J=8.5 Hz, 1H), 2.09-2.04 (m, 1H), 1.96-1.74 (m, 4H),1.54-1.32 (m, 20H), 1.03 (dd, J=9.0, 6.0 Hz, 1H), 0.84-0.79 (m, 2H) ppm;¹³C NMR (125 MHz, CDCl₃) δ 177.12, 173.43, 170.61, 167.07, 160.58,157.94, 155.27, 143.87, 141.14, 136.86, 134.47, 129.03, 124.86, 119.25,106.14, 75.04, 59.37, 56.26, 55.90, 54.03, 53.26, 50.27, 44.28, 43.56,36.61, 35.45, 34.67, 29.39, 28.74, 27.65, 27.51, 26.80, 25.57, 25.37,22.41, 19.65, 18.33, 14.68, 12.71 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₄₁H₅₆N₇O₁₀S⁺, 838.3804; found 838.3774.

(2R,6S,13aS,14aR,16aS,Z)-6-((S)-2-acetamido-2-cyclopentylacetamido)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-N-((1-methylcyclopropyl)sulfonyl)-5,16-dioxo-1,2,3,6,7,8,9,10,11,13a,14,15,16,16a-tetradecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecine-14a(5H)-carboxamide(AJ-68)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt 11 (0.25 g, 0.36 mmol) and N-Ac-cyclopentylglycine(0.075 g, 0.47 mmol) was treated with DIEA (0.50 mL, 2.87 mmol) and HATU(0.30 g, 0.79 mmol) to provide the target compound AJ-68 (0.30 g, 80%)as a white solid. ¹H NMR (500 MHz, CD₃OD) δ 7.76 (d, J=9.5 Hz, 1H), 7.27(d, J=3.0 Hz, 1H), 7.21 (dd, J=9.0, 3.0 Hz, 1H), 5.99 (br s, 1H), 5.70(q, J=8.5 Hz, 1H), 5.05 (t, J=9.0 Hz, 1H), 4.66 (t, J=8.5 Hz, 1H), 4.61(d, J=11.5 Hz, 1H), 4.40 (dd, J=11.0, 2.5 Hz, 1H), 4.10 (dd, J=11.5,3.5, Hz, 1H), 4.03 (d, J=9.0 Hz, 1H), 3.94 (s, 3H), 2.70-2.62 (m, 2H),2.58-2.51 (m, 4H), 2.44 (q, J=9.0 Hz, 1H), 1.99-1.85 (m, 6H), 1.73 (dd,J=8.0, 5.5 Hz, 1H), 1.68-1.16 (m, 22H), 0.90-0.84 (m, 2H) ppm; ¹³C NMR(125 MHz, CD₃OD) δ 179.36, 173.69, 173.28, 173.01, 169.51, 162.04,157.06, 146.26, 142.70, 136.84, 134.84, 129.25, 126.46, 119.76, 107.35,76.72, 60.76, 58.21, 56.27, 54.37, 52.44, 45.32, 43.48, 37.60, 35.98,33.18, 31.02, 30.19, 30.17, 28.62, 28.31, 27.83, 26.14, 25.77, 23.24,22.30, 21.74, 19.77, 18.44, 14.57, 13.01 ppm; HRMS (ESI) m/z: [M+H]⁺calcd for C₄₁H₅₆N₇O₉S⁺, 822.3855; found 822.3836.

Methyl(1-(((2R,6S,13aS,14aR,16aS,Z)-2-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-14a-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-5,16-dioxo-1,2,3,5,6,7,8,9,10,11,13a,14,14a,15,16,16a-hexadecahydrocyclopropa[e]pyrrolo[1,2-a][1,4]diazacyclopentadecin-6-yl)carbamoyl)cyclopentyl)carbamate(WK-25)

The same procedure was used as described above for compound P4-P5-2. Amixture of amine salt 11 (0.25 g, 0.36 mmol) andmethoxycarbonyl-L-cycloleucine (0.089 g, 0.48 mmol) was treated withDIEA (0.50 mL, 2.87 mmol) and HATU (0.30 g, 0.79 mmol) to provide thetarget compound WK-25 (0.20 g, 67%) as a white solid. ¹H NMR (500 MHz,CDCl₃) δ 10.41 (s, 1H), 8.08 (br s, 1H), 7.77 (d, J=9.0 Hz, 1H),7.18-7.15 (m, 2H), 6.86 (d, J=7.0 Hz, 1H), 5.96 (br s, 1H), 5.71 (q,J=9.0 Hz, 1H), 5.50 (br s, 1H), 5.00 (t, J=9.5 Hz, 1H), 4.62 (t, J=7.5Hz, 1H), 4.53 (br s, 1H), 4.36 (d, J=11.5 Hz, 1H), 4.14 (dd, J=11.0, 4.5Hz, 1H), 3.93 (s, 3H), 3.61 (s, 3H), 2.75-2.69 (m, 1H), 2.62-2.55 (m,1H), 2.51-2.46 (m, 4H), 2.14 (q, J=8.5 Hz, 2H), 1.96-1.45 (m, 18H),1.40-1.23 (m, 5H), 0.86-0.81 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ176.93, 173.94, 173.00, 167.34, 160.42, 156.24, 155.38, 144.41, 141.11,136.43, 134.46, 129.00, 125.24, 119.00, 106.17, 74.75, 67.04, 59.33,55.86, 52.96, 52.32, 51.64, 44.48, 38.73, 37.91, 36.61, 36.18, 34.62,32.23, 29.81, 27.82, 27.22, 26.04, 24.22, 22.67, 19.93, 18.24, 14.76,12.63 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₄₀H₅₄N₇O₁₀S⁺, 824.3647;found 824.3618.

Part 3. Linear HCV NS3/4A Protease Inhibitors

The synthesis of linear NS3/4A PIs with diverse P2 quinoxaline moietiesis outlined in Scheme S. The key Boc-protected P2 intermediates 4a-ewere prepared from the corresponding 3-substituted7-methoxy-quinoxalin-2-ones by an S_(N)2 displacement reaction with theactivated cis-hydroxyproline derivative as described previously.Deprotection of the Boc group and reaction with N-Boc-L-tert-leucineunder HATU coupling conditions gave the P2-P3 intermediates 5a-e. Afterester hydrolysis, the resulting acids 6a-e were coupled with the P1-P1′acylsulfonamide intermediates 7 and 8 to afford the target inhibitors 3,9b-e and 10a-e. The tert-butyl-capped compounds were converted to thecorresponding cyclopentyl derivatives in two steps, involving Bocdeprotection and reaction withN-(cyclopentyloxycarbonyloxy)-succinimide, to provide the desiredcompounds 11a-e and 12a-e.

The SAR exploration of 3 was focused on optimizing interactions of theP2 quinoxaline moiety and minimizing direct interactions with S2 subsiteresidues. In addition, modifications at the P1′ and the N-terminalcapping groups were also investigated. The potency and resistanceprofiles of the resulting linear PIs were evaluated using biochemicaland replicon assays. The enzyme inhibition constants (K_(i)) weredetermined against WT GT1a NS3/4A protease and resistant variants R155Kand D168A (Table 8). For a subset of compounds, cellular antiviralpotencies (EC₅₀) were determined using replicon-based antiviral assaysagainst WT HCV and resistant variants R155K, A156T, D168A, and D168V(Table 9). Grazoprevir (1) was used as a control in all assays.

Scheme 5. Synthesis of HCV NS3/4A Protease Inhibitors^(a)

-   -   ^(a)Reagents and conditions: (a) 4 N HCl in dioxane, CH₂Cl₂, RT,        3 h; (b) Boc-Tle-OH, HATU, DIEA, DMF, RT, 4 h; (c) LiOH.H₂O,        THF, H₂O, RT, 24 h; (d) HATU, DIEA, DMF, RT, 2 h; (e) 4 N HCl in        dioxane, RT, 3 h; (f)        N-(cyclopentyloxy-carbonyloxy)-succinimide, DIEA, CH₃CN, RT, 36        h.

Compared to the macrocyclic PIs 1 and 2, the linear analogue 3 exhibitedsignificantly lower potency against WT protease (K, =19 nM) andexperienced an even larger reduction in antiviral potency (EC₅₀=24 nM),as reported previously. Compound 3 was also less potent than 1 and 2against the resistant variants R155K, D168A and D168V in both enzymeinhibition and replicon assays. The significant potency losses for thelinear inhibitor 3 are likely due to the increase in conformationalflexibility and associated entropic penalty of binding to the protease.However, close examination of the overall resistance profile revealedthat fold losses in potency were generally lower for compound 3 than 1in both enzyme inhibition and replicon assays (Tables 10 and 9).Moreover, while 1 was highly susceptible to the A156T variant (EC₅₀=200nM), with >1600-fold loss in potency compared to WT, compound 3 showedbetter antiviral potency against this variant (EC₅₀=73 nM). The reducedsusceptibility to RASs, particularly at Ala156, observed for 3demonstrates that removal of the macrocyclic linker and the resultingconformational flexibility allows the inhibitor to adapt tosubstitutions in the S2 subsite.

To improve potency, analogues of inhibitor 3 with modifications at theP1′ and P4 capping groups were prepared and tested. Replacement of theP1′ cyclopropylsulfonamide with a more hydrophobic1-methylcyclopropyl-sulfonamide moiety generally improved potency of theresulting analogues. Thus, compared to 3, analogue 10a afforded a slightincrease in enzyme potency against WT protease and resistant variantsR155K and D168A. Similarly, replacing the tert-butyl P4 capping groupwith a bulkier cyclopentyl moiety in 11a provided compounds withimproved potency. Analogue 12a with the 1-methyl-cyclopropylsulfonamidemoiety at P1′ and cyclopentyl P4 capping group was 2- and 4-fold morepotent than 3 against the WT protease (K_(i)=6.9 nM) and D168A variant(K_(i)=145 nM), respectively. Thus, minor modifications at the P1′ andP4 moieties of inhibitor 3 provided analogues with improved potencyagainst WT protease and the D168A variant.

TABLE 8 Inhibitory activity against wild-type HCV NS3/4A protease anddrug resistant variants

Ki (nM) Compd R¹ R² WT R155K D168A 3 Et H  19 ± 2.7  17 ± 2.3 642 ± 10110a Et Me  16 ± 1.3  14 ± 1.1 385 ± 31  11a Et H 9.8 ± 2.0  15 ± 2.2 350± 30  12a Et Me 6.9 ± 0.5  13 ± 2.7 145 ± 14  9b Me H  18 ± 1.6 8.5 ±2.1 290 ± 24  10b Me Me  14 ± 2.1  14 ± 1.7 265 ± 26  11b Me H 9.2 ± 0.99.6 ± 0.9 144 ± 23  12b Me Me 7.1 ± 1.1  10 ± 1.3 140 ± 13  9c i-Pr H 32 ± 5.1 49 ± 11 1086 ± 137  10c i-Pr Me  29 ± 9.4  27 ± 5.6 1179 ±170  11c i-Pr H  17 ± 3.2 55 ± 11 985 ± 106 12c i-Pr Me  21 ± 2.6 43 ±11 1000 ± 80   9d Cl H 7.8 ± 1.1 2.2 ± 0.4 128 ± 16  10d Cl Me 6.1 ± 1.13.8 ± 0.6 119 ± 16  11d Cl H 3.8 ± 0.6 4.1 ± 0.5 99 ± 10 12d Cl Me 3.9 ±0.7 5.2 ± 0.8  51 ± 6.0 9e CF₃ H 87 ± 18  24 ± 3.3 723 ± 80  10e CF₃ Me 46 ± 9.6  12 ± 1.7 513 ± 50  11e CF₃ H  34 ± 8.3  26 ± 7.7 703 ± 63 12e CF₃ Me  22 ± 3.4  22 ± 6.9 516 ± 61  2 2.0 ± 0.1  3.1 ± 0.34 91 ± 101 0.20 ± 0.1  0.80 ± 0.3   40 ± 5.0

It has been shown that minimizing inhibitor interactions in the S2subsite resulted in an overall improvement in potency and resistanceprofiles. (Matthew, et al. 2017 J. Med. Chem. 60, 5699-5716.) Althoughthe P2 quinoxaline in 3 largely avoids direct interactions with residuesin the S2 subsite, the ethyl group at the 3-position of this moietymakes hydrophobic interactions with the hydrocarbon portion of theArg155 side chain as well as with Ala156. Thus, in an effort to optimizeinteractions with these residues, changes at the 3-position of P2quinoxaline moiety were explored. Based on the co-crystal structures andSAR results from the P1-P3 macrocyclic series,¹⁷ replacing the ethylgroup with a smaller methyl group at this position, while reducingoverall inhibitor interactions in the S2 subsite, was expected tomaintain key hydrophobic interactions with side chains of Arg155 andAla156. As anticipated, compound 9b incorporating the3-methylquinoxaline was 2-fold more potent than 3 against the R155K andD168A protease variants in enzyme inhibition assays. However, analogue10b with the 1-methylcyclopropylsulfonamide moiety at P1′ position didnot show much improvement in enzyme potency compared to 9b. Compounds11b and 12b with the cyclopentyl P4 capping group were slightly morepotent than the corresponding tert-butyl analogues 9b and 10b against WTand D168A. Furthermore, compounds 11b and 12b showed nanomolar potencyin replicon assays against WT HCV, and despite losing about 5-20-foldpotency, 12b maintained significant potency against all variants tested.Although both the 3-ethyl and 3-methyl-quinoxaline compounds showedsimilar potencies against WT and R155K protease variants, PIs with thesmaller methyl substituent were generally more potent against the D168Avariant. Together, the enzyme inhibition and replicon data indicate apreference for smaller substituents at the 3-position of the P2quinoxaline to maintain potency against resistant variants.

Next, a larger isopropyl group was incorporated in compounds 9c and 10cto further explore the optimal size of the substituent at the 3-positionof P2 quinoxaline that can be accommodated in the S2 subsite withoutcausing unfavorable interactions. These compounds displayed considerablylower potency compared to the 3-methyl- and 3-ethyl-quinoxalinecompounds across all variants in enzyme inhibition assays. Moreover,compounds with a larger isopropyl group at this position were highlysusceptible to RASs at Arg155 and Asp168, with K, values in themillimolar range against the D168A protease variant. Analogues 11c and12c, with a cyclopentyl P4 capping group, showed similar trends to thecorresponding tert-butyl analogues across all protease variants tested.These findings further showed that large substituents at the 3-positionof the P2 quinoxaline are detrimental to potency against resistantvariants.

After determining optimal size of the substituent at the 3-position ofthe P2 quinoxaline, isosteric replacements of the alkyl group withdifferent electronic properties were explored. Thus, a set of compoundsbearing a 3-chloroquinoxaline P2 moiety, with comparable size to the3-methylquinoxaline, was analyzed. In general, compounds with the3-chloroquinoxaline were significantly more potent than thecorresponding 3-ethyl- and 3-methyl-quinoxaline analogues. Compounds 9dand 10d, with a tert-butyl P4 capping group, showed about 2-fold betterpotency than the corresponding 3-methylquinoxaline analogues 9b and 10bagainst WT, R155K and D168A proteases. Similarly, the cyclopentyl-cappedcompounds 11d and 12d (WT K_(i)=3.8 and 3.9 nM, respectively) were morepotent than the corresponding 11b and 12b, showing excellent potencyagainst WT protease and resistant variants. In fact, both 11d and 12dexhibited K_(i) values against WT protease and resistant variants in thesame range as the macrocyclic inhibitor 2 (WT K_(i)=2.0 nM), indicatingthat potency of the quinoxaline-based linear PIs can be improvedsignificantly by SAR exploration. In replicon assays, the3-chloroquinoxaline compounds exhibited the best overall potency profileamong the linear compounds, with PIs 9d, 10d and 12d showing significantimprovement in replicon potency against the multidrug resistant HCVvariants D168A/V (EC₅₀=12-38 nM). However, these compounds were moresusceptible to the A156T substitution than the corresponding macrocyclicanalogues. The improved potency profiles of the 3-chloroquinoxalinecompounds compared to the corresponding 3-methylquinoxaline analoguesindicate that the chloro group likely renders more favorable electronicproperties to the quinoxaline moiety, which improves the critical π-πstacking interactions with catalytic residue His57.

TABLE 9 Antiviral activity against wild-type HCV and drug resistantvariants Replicon EC50 (nM) (fold change) Compd. WT R155K A156T D168AD168V 3 24 50 (2.1) 73 (3.0) >500 (>21) >500 (>21) 11b 10 48 (4.8) 164(16) 101 (10) 150 (15) 12b 4.5 28 (6.2) 87 (19) 45 (10) 59 (13)  9d 6.610 (1.5) 107 (16) 38 (5.8) 12 (1.8) 10d 6.3 10 (1.6) 100 (16) 30 (4.8)12 (1.9) 11d 7.4 40 (5.4) 292 (40) 50 (6.8) 54 (7.3) 12d 3.1 27 (8.7)163 (53) 25 (8.1) 23 (7.4) 2 0.33 1.8 (5.5) 9.7 (29) 6.3 (19) 9.1 (28) 10.12 1.9 (16) 200 (1667) 11 (92) 5.3 (44)

To further investigate the effect of electron-withdrawing groups on theactivity of the inhibitors, derivatives with a more electronegative,although relatively larger, 3-trifluoromethylquinoxaline were examined.In contrast to the 3-chloroquinoxaline inhibitors, compounds 9e and 10eshowed considerable loss in potency against WT protease. However,despite relatively lower potency against WT, the3-trifluoromethylquinoxaline analogues were slightly more potent thanthe corresponding 3-isopropylquinoxaline PIs against the resistantvariants R155K and D168A. Similar trends were observed for inhibitors11e and 12e with the cyclopentyl P4 capping groups. While it isdifficult to separate the effects of electronic properties of thechloro- and trifluoromethyl-quinoxaline moieties, it is likely that sizeplayed a more important role in determining the overall potency profileof these inhibitors.

In an effort to explain the observed potency and resistance profiles,crystal structures of three linear PIs incorporating different P2quinoxaline moieties were determined in complex with WT NS3/4A protease(Table 11). The crystal structures of co-complexes WT-12b, -12c and -12dwere compared with the previously determined structures of 1 and 3 (PDBIDs 3SUD and 5EQQ, respectively). These high-resolution (1.78-1.80 Å)structures provided details of protein-inhibitor interactions toelucidate the structural differences that underlie varied potency andsusceptibility to resistant variants.

The overall binding mode of linear inhibitors 12b-d is similar to thatof macrocyclic inhibitors 1-2 and the parent compound 3, where the P2quinoxaline predominately interacts with the catalytic triad residues(FIG. 14 ). These structures confirm that the quinoxaline moietymaintains this unique binding conformation irrespective ofmacrocyclization and the substituent at the 3-position. Inhibitors 12b-dspan the S1′-S4 pockets in the active site, with a conserved hydrogenbond network present in all WT NS3/4A protease structures. The hydrogenbonds between the P1 amide and the backbone carbonyl of Arg155 as wellas the P3 amide and Ala157 backbone are maintained. The P1′acylsulfonamide moiety is positioned in the oxyanion hole, stabilized byhydrogen bonds with His57, Gly137, Ser138 and Ser139. Although theoverall binding mode of linear analogues is similar to that of compound1, there are subtle changes in the binding of P2 quinoxaline that mayimpact inhibitor potency.

The differences between the WT co-crystal structures of 1 and3-methylquinoxaline inhibitor 12b occur predominantly in the S2 subsite.Relative to WT-1, the Asp168 side chain in the WT-12b structure isshifted to allow additional hydrogen bonding with the side chain ofArg155 (FIGS. 14A and 15A). This conformation of Asp168, which allowsthe P4 cyclopentyl capping group to occupy the S4 pocket, is observed inmost WT protease-inhibitor complexes. The 3-methylquinoxaline moiety isshifted away from the catalytic residues toward the S2 subsite relativeto the conformation of P2 quinoxaline in WT-1 structure. This shift wasalso observed in the parent compound 3, though to a lesser extent,likely to accommodate the larger ethyl group at the 3-position ofquinoxaline (FIG. 16 ). However, despite larger shift of the3-methylquinoxaline moiety, inhibitor 12b has an improved potencyprofile against resistant variants compared to 3, likely due to weakercontacts of the smaller methyl group with residues in the S2 subsitethat mutate to confer resistance. Thus, while a slight shift of the P2quinoxaline toward the S2 subsite does not appear to affect the overallpotency profile, the substituent at the 3-position of this moietysignificantly impacts inhibitor potency against resistant variants.

The shift of the quinoxaline moiety toward the S2 subsite residues wasalso observed in the WT-12c and WT-12d complexes (FIG. 15B-C), as wellas in WT-2 and other structures of the P1-P3 macrocyclic analogues.However, the crystal structure of inhibitor 12c with the3-isopropylquinoxaline revealed an additional rearrangement of the P2moiety. Compared to 1, the P2 quinoxaline in 12c, with a largerisopropyl substituent, packs less against the catalytic His57 and movesaway from the binding surface toward the solvent (FIG. 15B). Thismovement of the quinoxaline away from the catalytic His57 is notobserved in the inhibitor complexes with smaller substituents at the3-position (FIGS. 15A and 15C). Interestingly, this conformation isreminiscent of the conformation of 1 when bound to the A156T proteasevariant (PDB ID 3SUG) (FIG. 17 ), where the larger threonine residuecauses steric clash with the P2-P4 macrocycle. To accommodate the largerside chain in the A156T protease, inhibitor 1 undergoes a rearrangementresulting in the shift of the P2 quinoxaline moiety away from thebinding surface toward the solvent, weakening the critical T-ainteractions with the catalytic His57 (FIG. 17A). This alteredconformation of 1 results in dramatic potency losses against RASs atAla156.

Similar to the A156T-1 complex, the altered conformation of the3-isopropylquinoxaline results in significantly reduced interactionswith the catalytic His57. Any perturbation to the protease active sitedue to RASs may further reduce interactions with His57. Indeed, the3-isopropylquinoxaline compounds exhibit reduced potency against WTrelative to the parent compound 3 and are the most susceptible toresistant variants. These results suggest that modifications of theinhibitor scaffold that cause movement of the quinoxaline away fromHis57 toward the solvent are highly detrimental to potency. Whereas,movement of the quinoxaline away from His57 toward the S2 subsiteresidues has less of an effect on inhibitor potency when a smallersubstituent is present at the 3-position of P2 quinoxaline.

The 3-chloroquinoxaline series exhibited an excellent potency profileagainst WT and resistant variants even with a shift of the P2quinoxaline moiety toward the S2 subsite. Interestingly, comparison ofthe WT-12b and WT-12d structures (FIG. 15C) did not reveal anynoticeable difference in binding poses for the 3-methyl- and3-chloro-quinoxaline analogues that could explain the disparity ininhibitory activity. The electronic effects of the chloro group appearto improve stacking interactions of the quinoxaline moiety with thecatalytic residue His57, which are crucial for the binding of inhibitorswith a P2 quinoxaline moiety. Thus, enhancing interactions with thecatalytic triad residues by modifying the inhibitor P2 quinoxalinemoiety is likely to improve overall binding energy and potency profiles.

In summary, the SAR of quinoxaline-based linear HCV NS3/4A PIs have beenstudied using a structure-guided design strategy to improve potencyagainst resistant variants. Co-crystal structures of three inhibitorswith different P2 moieties bound to WT protease revealed the structuralbasis for the observed potency and resistance profiles. Inhibitors withsmall substituents at the 3-position of the P2 quinoxaline werepreferred for maintaining potency against resistant variants due todecreased interactions with the S2 subsite residues. Compounds withlarger groups at this position cause the P2 quinoxaline moiety to shiftout of the active site, weakening critical stacking interactions withthe catalytic His57. These findings further support that reducinginhibitor interactions with the S2 subsite residues in the proteaseactive site results in improved resistance profiles. Moreover, in theabsence of a macrocycle, the quinoxaline-based linear PIs can beoptimized by SAR exploration to provide compounds with potent activityagainst resistant variants.

TABLE 10 Inhibitory activity against wild-type HCV NS3/4A protease anddrug resistant variants

Ki (nM) (fold change) Compound R¹ R² WT R155K D168A 3 Et H  19 ± 2.7 17± 2.3 (0.9)  642 ± 101 (34) 10a Et Me  16 ± 1.3 14 ± 1.1 (0.9) 385 ± 31(24) 11a Et H 9.8 ± 2.0 15 ± 2.2 (1.5) 350 ± 30 (36) 12a Et Me 6.9 ± 0.513 ± 2.7 (1.9) 145 ± 14 (21) 9b Me H  18 ± 1.6 8.5 ± 2.1 (0.5)  290 ± 24(16) 10b Me Me  14 ± 2.1 14 ± 1.7 (1.0) 265 ± 26 (19) 11b Me H 9.2 ± 0.99.6 ± 0.9 (1.0)  144 ± 23 (16) 12b Me Me 7.1 ± 1.1 10 ± 1.3 (1.4) 140 ±13 (20) 9c i-Pr H  32 ± 5.1 49 ± 11 (1.5)  1086 ± 137 (34) 10c i-Pr Me 29 ± 9.4 27 ± 5.6 (0.9) 1179 ± 170 (41) 11c i-Pr H  17 ± 3.2 55 ± 11(3)    985 ± 106 (58) 12c i-Pr Me  21 ± 2.6 43 ± 11 (2.0)  1000 ± 80(48)  9d Cl H 7.8 ± 1.1 2.2 ± 0.4 (0.3)  128 ± 16 (16) 10d Cl Me 6.1 ±1.1 3.8 ± 0.6 (0.7)  119 ± 16 (31) 11d Cl H 3.8 ± 0.6 4.1 ± 0.5 (1.1)  99 ± 10 (26) 12d Cl Me 3.9 ± 0.7 5.2 ± 0.8 (1.3)    51 ± 6.0 (13) 9eCF₃ H 87 ± 18 24 ± 3.3 (0.3) 723 ± 80 (8)  10e CF₃ Me  46 ± 9.6 12 ± 1.7(0.3) 513 ± 50 (11) 11e CF₃ H  34 ± 8.3 26 ± 7.7 (0.8) 703 ± 63 (21) 12eCF₃ Me  22 ± 3.4 22 ± 6.9 (1.0) 516 ± 61 (24) 2 2.0 ± 0.1  3.1 ± 0.34(1.6)  91 ± 10 (46) 1 0.20 ± 0.1  0.80 ± 0.3 (4)       40 ± 5.0 (200)

TABLE 11 X-ray data collection and crystallographic refinementstatistics WT1a-12b WT1a-12c WT1a-12d PDB code: 6CVW 6CVX 6CVYResolution 1.78 Å 1.78 Å 1.80 Å Space group P2₁2₁2₁ P2₁2₁2₁ P2₁2₁2₁Molecules in AU^(a) 1 1 1 Cell dimensions a (Å) 55.2 55.3 55.5 b (Å)58.5 58.5 58.5 c (Å) 59.9 59.8 59.7 β (°) 90 90 90 Completeness (%) 98.399.1 96.4 Total reflections 70790 119454 116526 Unique reflections 1887019054 17991 Average I/σ 18.5 15.1 15.2 Redundancy 3.8 6.3 6.5 R_(sym)(%)^(b) 7.8 (25.6) 7.1 (27.3) 8.5 (30.7) RMSD^(c) in Bond lengths (Å)0.014 0.019 0.009 Bond angles (°) 1.4 1.5 1.1 R_(factor) (%)^(d) 14.915.6 14.7 R_(free) (%)^(e) 18.5 19.4 18.4 ^(a)AU, asymmetric unit.^(b)R_(sym) = Σ | I − <I>|/Σ I, where I = observed intensity, <I> =average intensity over symmetry equivalent; values in parentheses arefor the highest resolution shell. ^(c)RMSD, root mean square deviation.^(d)R_(factor) = Σ ∥ F_(o)| − |F_(c)∥/Σ|F_(o)|. ^(e)R_(free) wascalculated from 5% of reflections, chosen randomly, which were omittedfrom the refinement process.

Experimental

All reactions were performed in oven-dried round bottomed or modifiedSchlenk flasks fitted with rubber septa under argon atmosphere, unlessotherwise noted. All reagents and solvents, including anhydroussolvents, were purchased from commercial sources and used as received.Flash column chromatography was performed using silica gel (230-400mesh, EMD Millipore). Thin-layer chromatography (TLC) was performedusing silica gel (60 F-254) coated aluminum plates (EMD Millipore), andspots were visualized by exposure to ultraviolet light (UV), exposure toiodine adsorbed on silica gel, and/or exposure to an acidic solution ofp-anisaldehyde (anisaldehyde) followed by brief heating. 1H NMR and ¹³CNMR spectra were acquired on Varian Mercury 400 MHz and Bruker AvanceIII HD 500 MHz NMR instruments. Chemical shifts are reported in ppm (Sscale) with the residual solvent signal used as reference and couplingconstant (J) values are reported in hertz (Hz). Data are presented asfollows: chemical shift, multiplicity (s=singlet, d=doublet, dd=doubletof doublet, t=triplet, q=quartet, m=multiplet, br s=broad singlet),coupling constant in Hz, and integration. High-resolution mass spectra(HRMS) were recorded on a Thermo Scientific Orbitrap Velos Pro massspectrometer coupled with a Thermo Scientific Accela 1250 UPLC and anautosampler using electrospray ionization (ESI) in the positive mode.The purity of final compounds was determined by analytical HPLC and wasfound to be >95% pure. HPLC was performed on an Agilent system equippedwith a photodiode array detector under the following conditions: column,Agilent Zorbax Eclipse XDB RP-C₈ (5 m, 4.6×150 mm, 80 Å); solvent A, H2Ocontaining 0.1% trifluoroacetic acid (TFA), solvent B, CH3CN containing0.1% TFA; gradient, 0% B to 100% B over 10 min followed by 100% B over 3min; injection volume, 20 μL; flow rate, 1.4 mL/min. Retention times andpurity data for each target compound are provided in the experimentalsection.

Synthesis of Intermediates and Final Compounds 1-(tert-Butyl) 2-methyl(2S,4R)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(4a)

A solution of 3-ethyl-7-methoxyquinoxalin-2(1H)-one¹ (3.0 g, 14.7 mmol)in anhydrous NMP (45 mL) was treated with Cs₂CO₃ (7.40 g, 22.7 mmol).After stirring the reaction mixture at room temperature for 15 min,brosylated cis-hydroxyproline derivative 1-(tert-butyl) 2-methyl(2S,4S)-4-(((4-bromophenyl)sulfonyl)oxy)pyrrolidine-1,2-dicarboxylate(6.20 g, 13.3 mmol) was added in one portion. The reaction mixture washeated to 55° C., stirred for 4 h, and then another portion ofbrosylated cis-hydroxyproline derivative (0.48 g, 1.0 mmol) was added.The resulting reaction mixture was stirred at 55° C. for additional 2 h,cooled to room temperature, quenched with aqueous 1 N HCl solution (150mL), and extracted with EtOAc (300 mL). The organic fraction was washedsuccessively with saturated aqueous NaHCO₃ and NaCl (150 mL each), dried(Na₂SO₄), filtered, and evaporated under reduced pressure. The residuewas purified by flash column chromatography using 15-30% EtOAc/hexanesas the eluent to provide 4a (5.50 g, 87%) as a white foamy solid. ¹H NMR(400 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.85 (d, J=9.0Hz, 1H), 7.18 (m, 1H), 7.11 (d, J=2.8 Hz, 1H), 5.73 (br s, 1H), 4.47 (t,J=8.0 Hz, 1H), 3.98-3.86 (m, 5H), 3.78 (s, 3H), 2.92 (q, J=7.2 Hz, 2H),2.68-2.60 (m, 1H), 2.43-2.36 (m, 1H), 1.43 (s, 9H), 1.31 (t, J=7.2 Hz,3H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.56, 160.59, 155.38, 154.02,148.95, 141.26, 134.12, 129.07, 119.02, 106.11, 80.76, 73.81, 58.43,55.93, 52.73, 52.40, 36.88, 28.47, 26.68, 11.97 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₂H₃₀N₃O₆, 432.2129; found 432.2135.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(4b)

The same procedure was used as described above for compound 4a.7-Methoxy-3-methylquinoxalin-2(1H)-one¹ (6.2 g, 32.6 mmol) in NMP (100mL) was treated with Cs₂CO₃ (16.0 g, 49.0 mmol) and activatedcis-hydroxyproline derivative (15.0 g, 32.3 mmol) to provide 4b (10.0 g,74%) as a white foamy solid. ¹H NMR (500 MHz, CDCl₃) (mixture ofrotamers, major rotamer) o 7.80 (d, J=9.0 Hz, 1H), 7.17 (dd, J=9.0, 3.0Hz, 1H), 7.11 (d, J=2.5 Hz, 1H), 5.71 (br s, 1H), 4.48 (t, J=8.0 Hz,1H), 3.99-3.91 (m, 4H), 3.87 (d, J=12.5 Hz, 1H), 3.78 (s, 3H), 2.67-2.58(m, 1H), 2.56 (s, 3H), 2.43-2.37 (m, 1H), 1.43 (s, 9H) ppm; ¹³C NMR (125MHz, CDCl₃) δ 173.36, 160.24, 155.51, 153.81, 144.60, 141.04, 134.22,128.95, 118.63, 105.95, 80.54, 73.59, 58.20, 55.68, 52.48, 52.20, 36.70,28.26, 19.93 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₁H₂₈N₃O₆, 418.1973;found 418.1976.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(4c)

The same procedure was used as described above for compound 4a.3-Isopropyl-7-methoxyquinoxalin-2(1H)-one¹ (4.0 g, 18.3 mmol) in NMP (65mL) was treated with Cs₂CO₃ (9.0 g, 27.6 mmol) and activatedcis-hydroxyproline derivative (8.30 g, 17.9 mmol) to provide 4c (7.30 g,90%) as a colorless gummy solid. ¹H NMR (500 MHz, CDCl₃) (mixture ofrotamers, major rotamer) δ 7.83 (d, J=8.0 Hz, 1H), 7.16 (d, J=8.4 Hz,1H), 7.10 (s, 1H) 5.74 (br s, 1H), 4.48 (t, J=7.5 Hz, 1H), 3.92-3.87 (m,5H), 3.78 (s, 3H), 3.41-3.36 (m, 1H), 2.68-2.59 (m, 1H), 2.42-2.35 (m,1H), 1.43 (s, 9H), 1.31 (t, J=7.0 Hz, 6H) ppm; ¹³C NMR (125 MHz, CDCl₃)δ 173.37, 160.19, 154.62, 153.82, 152.00, 140.68, 134.31, 129.39,118.41, 105.80, 80.49, 73.36, 58.28, 55.67, 52.58, 52.19, 36.68, 30.81,28.25, 20.43, 20.38 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₃H₃₂N₃O₆,446.2286; found 446.2287.

1-(tert-butyl) 2-methyl(2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(4d)

The same procedure was used as described above for compound 4a.3-Chloro-7-methoxyquinoxalin-2(1H)-one² (4.0 g, 19.0 mmol) in NMP (60mL) was treated with Cs₂CO₃ (9.30 g, 28.6 mmol) and activatedcis-hydroxyproline derivative (8.40 g, 18.1 mmol) to provide 4d (6.30 g,76%) as an off-white foamy solid. ¹H NMR (400 MHz, CDCl₃) (mixture ofrotamers, major rotamer) δ 7.80 (d, J=8.8 Hz, 1H), 7.21 (dd, J=8.8, 2.8Hz, 1H), 7.12 (d, J=2.8 Hz, 1H), 5.69 (br s, 1H), 4.52 (t, J=7.6 Hz,1H), 4.0-3.94 (s, 4H), 3.88 (d, J=12.8 Hz, 1H), 3.78 (s, 3H), 2.72-2.62(m, 1H), 2.45-2.37 (m, 1H), 1.43 (s, 9H) ppm; ¹³C NMR (400 MHz, CDCl₃) δ173.32, 162.35, 153.84, 152.48, 141.03, 136.11, 134.06, 129.97, 119.95,105.83, 80.60, 75.02, 58.10, 55.81, 52.36, 52.10, 36.64, 28.27 ppm; HRMS(ESI) m/z: [M+H]⁺ calcd for C₂₀H₂₅ClN₃O₆, 438.1426; found 438.1438.

1-(tert-Butyl) 2-methyl(2S,4R)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-1,2-dicarboxylate(4e)

The same procedure was used as described above for compound 4a.7-Methoxy-3-(trifluoromethyl)quinoxalin-2(1H)-one¹ (4.76 g, 19.5 mmol)in anhydrous NMP (65 mL) was treated with Cs₂CO₃ (9.80 g, 30.0 mmol) andactivated cis-hydroxyproline derivative (9.0 g, 19.4 mmol) to provide 4e(6.50 g, 71%) as a pale yellow foamy solid. ¹H NMR (500 MHz, CDCl₃)(mixture of rotamers, major rotamer) δ 7.77 (d, J=9.0 Hz, 1H), 7.48-7.43(m, 2H), 5.76 (br s, 1H), 4.50 (t, J=8.0 Hz, 1H), 3.97-3.91 (m, 5H),3.78 (s, 3H), 2.69-2.64 (m, 1H), 2.41-2.34 (m, 1H), 1.42 (s, 9H) ppm;¹³C NMR (125 MHz, CDCl₃) δ 173.43, 159.58, 153.98, 152.11, 138.39,137.22, 127.99, 125.73, 120.70 (q, J=273.4 Hz), 107.64, 80.69, 74.62,58.27, 56.02, 52.32, 52.11, 36.70, 28.34 ppm; ¹⁹F NMR (470 MHz, CDCl₃);-67.73 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₁H₂₅F₃N₃O₆, 472.1690;found 472.1689.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoyl)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(5a)

A solution of P2 intermediate 4a (2.75 g, 6.4 mmol) in anhydrous CH₂Cl₂(20 mL) was treated with a solution of 4 N HCl in 1,4-dioxane (20 mL).After stirring the reaction mixture at room temperature for 3 h,solvents were evaporated under reduced pressure, and the residue wasdried under high vacuum. The pale yellow solid was triturated withdiethyl ether (20 mL), filtered and washed with diethyl ether diethylether (3×5 mL) to yield the proline amine salt (2.30 g, 98%) as anoff-white powder.

A mixture of above amine salt (1.15 g, 3.1 mmol) and Boc-Tle-OH (0.88 g,3.8 mmol) in anhydrous DMF (20 mL) was treated with DIEA (2.52 mL, 15.2mmol) and HATU (2.17 g, 5.7 mmol). The resulting reaction mixture wasstirred at room temperature for 4 h, then diluted with EtOAc (150 mL),and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (75 mL each). The organic portion wasdried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash chromatography using 25-30% EtOAc/hexanesas the eluent to provide 5a (1.45 g, 85%) as a white foamy solid. ¹H NMR(400 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.87 (d, J=9.2Hz, 1H), 7.19 (dd, J=8.8, 2.8 Hz, 1H), 7.13 (d, J=2.8 Hz, 1H), 5.86 (brs, 1H), 5.18 (d, J=9.2 Hz, 1H), 4.73 (t, J=8.4 Hz, 1H), 4.27-4.22 (m,2H), 4.11-4.04 (m, 1H), 3.94 (s, 3H), 3.78 (s, 3H), 2.87 (q, J=7.2 Hz,2H), 2.71-2.65 (m, 1H), 2.39-2.31 (m, 1H), 1.33 (s, 9H), 1.27 (t, J=7.2Hz, 3H), 1.05 (s, 9H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.50, 171.60,160.57, 155.92, 155.11, 149.02, 141.11, 134.13, 129.13, 118.99, 106.20,79.79, 74.37, 58.76, 58.19, 55.92, 53.92, 52.57, 35.85, 35.23, 28.43,26.50, 11.85 ppm; HRMS (ESI) m/z: [M+Na]⁺ calcd for C₂₈H₄₁N₄O₇,545.2970; found 545.2973.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoyl)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(5b)

The same procedure was used as described above for compound 5a. Compound4b (3.60 g, 8.6 mmol) was treated with 4 N HCl (25 mL) to afford theproline amine salt (3.0 g, 8.5 mmol), which was coupled with Boc-Tle-OH(2.40 g, 10.4 mmol) using DIEA (7.0 mL, 42.4 mmol) and HATU (5.65 g,14.8 mmol) to provide 5b (3.50 g, 78%) as a white foamy solid. ¹H NMR(500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.80 (d, J=9.0Hz, 1H), 7.18 (dd, J=9.0, 2.5 Hz, 1H), 7.12 (d, J=3.0 Hz, 1H), 5.84 (brs, 1H), 5.18 (d, J=9.5 Hz, 1H), 4.75 (t, J=8.5 Hz, 1H), 4.27-4.22 (m,2H), 4.07 (dd, J=11.5, 4.5 Hz, 1H), 3.94 (s, 3H), 3.77 (s, 3H),2.70-2.65 (m, 1H), 2.52 (s, 3H), 2.38-2.32 (m, 1H), 1.34 (s, 9H), 1.05(s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 172.42, 171.57, 160.36, 155.87,155.39, 144.86, 141.05, 134.51, 129.15, 118.76, 106.19, 79.71, 74.30,58.70, 58.03, 55.79, 53.81, 52.48, 35.70, 35.15, 28.36, 26.42, 19.97ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₇H₃₉N₄O₇, 531.2813; found531.2807.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoyl)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(5c)

The same procedure was used as described above for compound 5a. Compound4c (1.30 g, 2.92 mmol) was treated with 4 N HCl (12 mL) to afford theproline amine salt (1.05 g, 2.75 mmol), which was coupled withBoc-Tle-OH (0.83 g, 3.60 mmol) using DIEA (2.38 mL, 14.4 mmol) and HATU(1.85 g, 4.86 mmol) to provide 5c (1.30 g, 85%) as a white foamy solid.¹H NMR (500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ 7.83 (d,J=9.0 Hz, 1H), 7.17 (dd, J=9.0, 3.0 Hz, 1H), 7.11 (d, J=3.0 Hz, 1H),5.88 (br s, 1H), 5.20 (d, J=9.5 Hz, 1H), 4.72 (t, J=8.5 Hz, 1H),4.26-4.21 (m, 2H), 4.07 (dd, J=11.5, 4.0 Hz, 1H), 3.94 (s, 3H), 3.77 (s,3H), 3.39-3.33 (m, 1H), 2.71-2.65 (m, 1H), 2.38-2.32 (m, 1H), 1.33 (s,9H), 1.28 (t, J=7.0 Hz, 6H), 1.05 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃)δ 172.41, 171.45, 160.33, 155.77, 154.47, 152.19, 140.67, 134.59,129.56, 118.57, 106.01, 79.64, 74.04, 58.66, 58.14, 55.78, 53.91, 52.46,35.88, 35.16, 30.80, 28.36, 26.40, 20.61, 20.52 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₂₉H₄₃N₄O₇, 559.3126; found 559.3112.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoyl)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(5d)

The same procedure was used as described above for compound 5a. Compound4d (1.05 g, 2.40 mmol) was treated with 4 N HCl (10 mL) to afford theproline amine salt (0.89 g, 2.40 mmol), which was coupled withBoc-Tle-OH (0.66 g, 2.86 mmol) using DIEA (1.90 mL, 11.5 mmol) and HATU(1.41 g, 3.72 mmol) to provide 5d (1.0 g, 76%) as an off-white foamysolid. ¹H NMR (500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ7.81 (d, J=9.0 Hz, 1H), 7.22 (dd, J=9.0, 2.5 Hz, 1H), 7.15 (d, J=3.0 Hz,1H), 5.81 (br s, 1H), 5.21 (d, J=10.0 Hz, 1H), 4.79 (t, J=8.5 Hz, 1H),4.31 (d, J=12.0 Hz, 1H), 4.21 (d, J=10.0 Hz, 1H), 4.09 (dd, J=11.5, 4.0Hz, 1H), 3.96 (s, 3H), 3.78 (s, 3H), 2.74-2.68 (m, 1H), 2.40-2.34 (m,1H), 1.32 (s, 9H), 1.04 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 172.36,171.54, 161.40, 155.87, 152.36, 140.99, 136.27, 134.26, 129.05, 120.05,106.05, 79.77, 75.69, 58.63, 58.02, 55.92, 53.43, 52.50, 35.74, 34.98,28.36, 26.40 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₆H₃₆ClN₄O₇,551.2267; found 551.2257.

Methyl(2S,4R)-1-((S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoyl)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidine-2-carboxylate(5e)

The same procedure was used as described above for compound 5a. Compound4e (1.30 g, 2.76 mmol) was treated with 4 N HCl (10 mL) to afford theproline amine salt (1.10 g, 2.70 mmol), which was coupled withBoc-Tle-OH (0.81 g, 3.50 mmol) using DIEA (2.30 mL, 14.0 mmol) and HATU(2.0 g, 5.25 mmol) to provide 5e (1.50 g, 95%) as a pale yellow foamysolid. ¹H NMR (500 MHz, CDCl₃) (mixture of rotamers, major rotamer) δ7.78 (d, J=9.0 Hz, 1H), 7.47 (dd, J=9.5, 3.0 Hz, 1H), 7.43 (d, J=2.5 Hz,1H), 5.87 (br s, 1H), 5.22 (d, J=9.5 Hz, 1H), 4.74 (t, J=8.5 Hz, 1H),4.27 (d, J=12.0 Hz, 1H), 4.20 (d, J=9.5 Hz, 1H), 4.11-4.07 (m, 1H), 3.94(s, 3H), 3.77 (s, 3H), 2.71-2.66 (m, 1H), 2.38-2.32 (m, 1H), 1.30 (s,9H), 1.03 (s, 9H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 172.36, 171.47,159.64, 155.84, 151.89, 138.51, 137.09, 134.59 (q, J=35.9 Hz), 128.04,125.73, 120.69 (d, J=273.8 Hz), 107.65, 79.69, 75.05, 58.58, 57.92,56.03, 53.47, 52.49, 35.75, 34.97, 28.26, 26.37 ppm; ¹⁹F NMR (470 MHz,CDCl₃); -67.84 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₂₇H₃₆F₃N₄O₇,585.2531; found 585.2516.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(3)

A solution of P2-P3 intermediate 5a (1.80 g, 3.31 mmol) in THF-H₂Omixture (1:1, 50 mL) was treated with LiOH.H₂O (0.46 g, 11.0 mmol). Theresulting reaction mixture was stirred at room temperature for 24 h. Thereaction mixture was cooled to −5° C., acidified to a pH of 2.0 by slowaddition of aqueous 0.50 N HCl (˜75 mL), and extracted with EtOAc (2×150mL). The organic portions were washed separately with saturated aqueousNaCl (75 ml), dried (Na₂SO₄), filtered, and evaporated under reducedpressure. The gummy residue was dissolved in CHCl₃ (20 mL), concentratedunder reduced pressure, and the residue was dried under high vacuumovernight to yield the acid 6a (1.75 g, 100%) as a white foamy solid.

A mixture of acid 6a (0.88 g, 1.64 mmol) and P1-P1′ amine salt 7³ (0.48g, 1.80 mmol) in anhydrous DMF (15 mL) was treated with DIEA (1.10 mL,6.60 mmol) and HATU (0.94 g, 2.46 mmol). The resulting reaction mixturewas stirred at room temperature for 2 h, then diluted with EtOAc (100mL) and washed successively with aqueous 0.5 N HCl, saturated aqueousNaHCO₃, and saturated aqueous NaCl (50 mL each). The organic portion wasdried (Na₂SO₄), filtered, and evaporated under reduced pressure. Theresidue was purified by flash chromatography using 50-80% EtOAc/hexanesas the eluent to provide compound 3 (0.95 g, 78%) as a white solid. ¹HNMR (400 MHz, CDCl₃) δ 10.08 (s, 1H), 7.84 (d, J=9.2 Hz, 1H), 7.20-7.14(m, 2H), 7.07 (s, 1H), 5.90 (br s, 1H), 5.79-5.72 (m, 1H), 5.28-5.22 (m,2H), 5.15 (d, J=10.4 Hz, 1H), 4.48 (t, J=8.4 Hz, 1H), 4.30 (d, J=12.0Hz, 1H), 4.24 (d, J=9.6 Hz, 1H), 4.03 (dd, J=11.6, 3.2 Hz, 1H), 3.94 (s,3H), 2.94-2.83 (m, 3H), 2.56-2.52 (m, 2H), 2.12 (q, J=8.4 Hz, 1H), 1.97(dd, J=8.0, 6.0 Hz, 1H), 1.48 (dd, J=9.2, 5.6 Hz, 1H), 1.40-1.22 (m,13H), 1.10-0.96 (m, 12H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.05, 172.77,168.64, 160.56, 155.87, 154.99, 148.86, 141.05, 134.51, 132.76, 129.32,119.01, 118.85, 106.19, 80.06, 74.37, 60.09, 58.96, 55.92, 54.51, 42.05,38.85, 35.81, 35.75, 34.51, 31.49, 28.43, 26.71, 22.63, 11.84, 6.50,6.45 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₆H₅₁N₆O₉S, 743.3433; found743.3431. Anal. RP-HPLC: t_(R) 9.57 min, purity 97%.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(9b)

The same procedure was used as described above for compound 3. Ester 5b(1.30 g, 2.45 mmol) was treated with LiOH.H₂O (0.36 g, 8.60 mmol) toafford acid 6b (1.25 g, 2.42 mmol). A portion of acid 6b (0.62 g, 1.20mmol) was reacted with amine salt 7 (0.40 g, 1.50 mmol) using DIEA (0.80mL, 4.84 mmol) and HATU (0.70 g, 1.84 mmol) to provide compound 9b (0.64g, 74%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.08 (s, 1H), 7.79(d, J=9.2 Hz, 1H), 7.18 (dd, J=8.8, 2.4 Hz, 1H), 7.13 (d, J=2.8 Hz, 2H),5.86 (br s, 1H), 5.80-5.71 (m, 1H), 5.28-5.23 (m, 2H), 5.13 (d, J=10.8Hz, 1H), 4.51 (t, J=8.4 Hz, 1H), 4.30 (d, J=11.6 Hz, 1H), 4.24 (d, J=9.2Hz, 1H), 4.03 (dd, J=12.0, 4.0 Hz, 1H), 3.94 (s, 3H), 2.93-2.86 (m, 1H),2.56-2.50 (m, 5H), 2.11 (q, J=9.2 Hz, 1H), 1.95 (dd, J=8.0, 6.0 Hz, 1H),1.47 (dd, J=9.2, 5.6 Hz, 1H), 1.38-1.30 (m, 10H), 1.07-0.97 (m, 12H)ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.89, 172.49, 168.48, 160.25, 155.67,155.12, 144.48, 140.89, 134.31, 132.51, 128.94, 118.78, 118.64, 106.0,79.84, 74.25, 59.79, 58.72, 55.68, 54.23, 41.83, 35.55, 35.42, 34.21,31.23, 28.22, 26.48, 22.32, 19.81, 6.27, 6.22 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₃₅H₄₉N₆O₉S, 729.3276; found 729.3283. Anal. RP-HPLC:t_(R) 9.13 min, purity 99%.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(9c)

The same procedure was used as described above for compound 3. Ester 5c(2.25 g, 4.03 mmol) was treated with LiOH.H₂O (0.68 g, 16.1 mmol) toafford acid 6c (2.15 g, 3.95 mmol). A portion of acid 6c (1.0 g, 1.84mmol) was coupled with amine salt 7 (0.60 g, 2.25 mmol) using DIEA (1.25mL, 7.40 mmol) and HATU (1.0 g, 2.63 mmol) to provide compound 9c (1.25g, 90%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.11 (s, 1H), 7.83(d, J=9.2 Hz, 1H), 7.18 (dd, J=8.8, 2.4 Hz, 1H), 7.12 (d, J=2.8 Hz, 1H),7.02 (s, 1H), 5.91 (br s, 1H), 5.82-5.73 (m, 1H), 5.28-5.23 (m, 2H),5.14 (d, J=10.4 Hz, 1H), 4.46 (t, J=8.4 Hz, 1H), 4.29-4.22 (m, 2H), 4.06(dd, J=11.6, 4.0 Hz, 1H), 3.94 (s, 3H), 3.37-3.30 (m, 1H), 2.94-2.87 (m,1H), 2.57-2.49 (m, 2H), 2.12 (q, J=8.4 Hz, 1H), 1.96 (dd, J=8.4, 6.0 Hz,1H), 1.48 (dd, J=9.6, 6.0 Hz, 1H), 1.40-1.20 (m, 16H), 1.05-0.95 (m,12H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.79, 172.42, 168.52, 160.23,155.60, 154.19, 151.78, 140.52, 134.42, 132.55, 129.37, 118.61, 105.81,79.78, 74.02, 59.97, 58.68, 55.68, 54.34, 41.75, 35.70, 35.57, 34.37,31.25, 30.67, 28.21, 26.47, 22.57, 20.51, 20.44, 6.29, 6.21 ppm; HRMS(ESI) m/z: [M+H]⁺ calcd for C₃₇H₅₃N₆O₉S, 757.3589; found 757.3588. Anal.RP-HPLC: t_(R)10.13 min, purity 98%.

tert-Butyl((S)-1-((2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(9d)

The same procedure was used as described above for compound 3. Ester 5d(2.0 g, 3.63 mmol) was treated with LiOH.H₂O (0.60 g, 14.3 mmol) toafford acid 6d (1.90 g, 3.54 mmol). A portion of acid 6d (0.92 g, 1.71mmol) was coupled with amine salt 7 (0.50 g, 1.88 mmol) using DIEA (1.15mL, 6.96 mmol) and HATU (0.95 g, 2.50 mmol) to provide compound 9d (1.0g, 78%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.07 (s, 1H), 7.81(d, J=8.8 Hz, 1H), 7.26-7.22 (1H), 7.18 (d, J=2.4 Hz, 1H), 7.04 (s, 1H),5.87 (br s, 1H), 5.81-5.74 (m, 1H), 5.29-5.20 (m, 2H), 5.14 (d, J=10.4Hz, 1H), 4.55 (t, J=8.4 Hz, 1H), 4.37 (d, J=11.6 Hz, 1H), 4.21 (d, J=9.6Hz, 1H), 4.05 (dd, J=12.0, 3.6 Hz, 1H), 3.96 (s, 3H), 2.93-2.88 (m, 1H),2.57 (dd, J=7.6, 2.8 Hz, 2H), 2.12 (q, J=8.8 Hz, 1H), 1.98 (dd, J=7.6,6.0 Hz, 1H), 1.48 (dd, J=9.6, 6.0, 1H), 1.38-1.29 (m, 10H), 1.09-0.98(m, 12H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.94, 172.63, 168.57, 161.46,155.82, 152.21, 141.01, 136.09, 134.25, 132.65, 129.00, 120.22, 118.77,106.05, 80.04, 75.77, 60.55, 59.97, 58.85, 54.01, 42.01, 35.69, 35.53,34.36, 31.39, 28.34, 26.60, 22.46, 6.40, 6.35 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₃₄H₄₆ClN₆O₉S, 749.2730; found 749.2736. Anal. RP-HPLC:t_(R) 9.82 min, purity 97%.

tert-Butyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(9e)

The same procedure was used as described above for compound 3. Ester 5e(1.60 g, 2.74 mmol) was treated with LiOH.H₂O (0.40 g, 9.53 mmol) toafford acid 6e (1.56 g, 2.74 mmol). A portion of acid 6e (0.78 g, 1.37mmol) was coupled with amine salt 7 (0.45 g, 1.69 mmol) using DIEA (0.95mL, 5.75 mmol) and HATU (0.85 g, 2.24 mmol) to provide compound 9e (0.80g, 75%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.09 (s, 1H),7.80 (d, J=8.8 Hz, 1H), 7.48 (dd, J=8.8, 2.8 Hz, 1H), 7.42 (d, J=2.8 Hz,1H), 7.15 (s, 1H), 5.92 (br s, 1H), 5.81-5.72 (m, 1H), 5.29-5.23 (m,2H), 5.14 (d, J=11.2 Hz, 1H), 4.50 (t, J=8.8 Hz, 1H), 4.32 (d, J=12.0Hz, 1H), 4.19 (d, J=9.6 Hz, 1H), 4.04 (dd, J=12.4, 4.0 Hz, 1H), 3.94 (s,3H), 2.93-2.87 (m, 1H), 2.53 (dd, J=8.8, 2.8 Hz, 2H), 2.13 (q, J=8.4 Hz,1H), 1.96 (dd, J=8.4, 6.0 Hz, 1H), 1.48 (dd, J=9.6, 6.0 Hz, 1H),1.36-1.32 (m, 1H), 1.28 (s, 9H), 1.05-0.96 (m, 12H) ppm; ¹³C NMR (100MHz, CDCl₃) δ 172.74, 172.37, 168.52, 159.38, 155.61, 151.59, 138.37,136.95, 134.24 (q, J=35.8 Hz), 132.54, 127.97, 125.70, 120.57 (d,J=273.6 Hz), 118.60, 106.42, 79.76, 75.0, 59.79, 58.60, 55.90, 53.93,41.79, 35.57, 35.45, 34.27, 31.24, 28.11, 26.43, 22.45, 6.26, 6.19 ppm;HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₅H₄₆F₃N₆O₉S, 783.2994; found783.3000. Anal. RP-HPLC: t_(R) 9.89 min, purity 98%.

tert-Butyl((S)-1-((2S,4R)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(10a)

The same procedure was used as described above for compound 3. Acid 6a(0.73 g, 1.38 mmol) was coupled with amine salt 84 (0.45 g, 1.60 mmol)using DIEA (0.95 mL, 5.75 mmol) and HATU (0.85 g, 2.24 mmol) to providecompound 10a (0.80 g, 77%) as a white solid. ¹H NMR (500 MHz, CDCl₃) δ9.80 (s, 1H), 7.83 (d, J=9.0 Hz, 1H), 7.20-7.15 (m, 3H), 5.89 (br s,1H), 5.72-5.64 (m, 1H), 5.28 (d, J=17.0 Hz, 1H), 5.21 (d, J=9.5 Hz, 1H),5.15 (d, J=10.0 Hz, 1H), 4.57 (t, J=8.0 Hz, 1H), 4.31 (d, J=12.0 Hz,1H), 4.24 (d, J=9.5 Hz, 1H), 4.02 (dd, J=12.0, 4.0 Hz, 1H), 3.95 (s,3H), 2.86 (q, J=7.5 Hz, 2H), 2.67-2.61 (m, 1H), 2.57-2.52 (m, 1H), 2.11(q, J=8.5 Hz, 1H), 1.94 (dd, J=8.0, 6.0 Hz, 1H), 1.73-1.68 (m, 1H),1.64-1.60 (m, 1H), 1.50 (s, 3H), 1.39 (dd, J=9.0, 6.5 Hz, 1H), 1.33 (s,9H), 1.27 (t, J=7.5 Hz, 3H), 1.03 (s, 9H), 0.90-0.81 (m, 2H) ppm; ¹³CNMR (125 MHz, CDCl₃) δ 173.56, 172.86, 167.24, 160.42, 155.77, 154.92,148.85, 140.95, 134.54, 132.74, 129.28, 118.89, 118.84, 106.14, 79.98,74.18, 59.64, 58.95, 55.83, 54.36, 42.55, 36.69, 35.58, 35.06, 34.16,28.34, 26.60, 21.42, 18.54, 14.17, 13.66, 11.70 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₃₇H₅₃N₆O₉S, 757.3589; found 757.3587. Anal. RP-HPLC:t_(R) 9.78 min, purity 99%.

tert-Butyl((S)-1-((2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(10b)

The same procedure was used as described above for compound 3. Acid 6b(0.62 g, 1.20 mmol) was coupled with amine salt 8 (0.40 g, 1.43 mmol)using DIEA (0.80 mL, 4.84 mmol) and HATU (0.70 g, 1.84 mmol) to providecompound 10b (0.70 g, 79%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ9.80 (s, 1H), 7.80 (d, J=9.2 Hz, 1H), 7.23 (s, 1H), 7.20-7.14 (m, 2H),5.86 (br s, 1H), 5.72-5.63 (m, 1H), 5.29-5.21 (m, 2H), 5.15 (d, J=10.0Hz, 1H), 4.60 (t, J=8.4 Hz, 1H), 4.32 (d, J=11.2 Hz, 1H), 4.23 (d, J=9.2Hz, 1H), 4.01 (dd, J=11.6, 3.6 Hz, 1H), 3.94 (s, 3H), 2.69-2.61 (m, 1H),2.57-2.50 (m, 4H), 2.10 (q, J=8.4 Hz, 1H), 1.93 (dd, J=8.0, 5.6 Hz, 1H),1.73-1.67 (m, 1H), 1.63-1.59 (m, 1H), 1.50 (s, 3H), 1.37 (dd, J=9.6, 6.0Hz, 1H), 1.33 (s, 9H), 1.02 (s, 9H), 0.88-0.81 (m, 2H) ppm; ¹³C NMR (100MHz, CDCl₃) δ 173.67, 172.99, 167.35, 160.48, 155.89, 155.39, 144.74,141.14, 134.57, 132.82, 129.19, 119.0, 106.25, 80.10, 74.40, 59.69,59.04, 55.92, 54.41, 42.64, 36.74, 35.61, 35.12, 34.14, 28.45, 26.71,21.44, 20.08, 18.62, 14.26, 13.72 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₆H₅₁N₆O₉S, 743.3433; found 743.3428. Anal. RP-HPLC: t_(R) 9.34 min,purity 99%.

tert-Butyl((S)-1-((2S,4R)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(10c)

The same procedure was used as described above for compound 3. Acid 6c(1.0 g, 1.84 mmol) was coupled with amine salt 8 (0.67 g, 2.39 mmol)using DIEA (1.25 mL, 7.56 mmol) and HATU (1.0 g, 2.63 mmol) to providecompound 10c (1.20 g, 85%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ9.85 (s, 1H), 7.83 (d, J=9.2 Hz, 1H), 7.18-7.12 (m, 3H), 5.89 (br s,1H), 5.73-5.64 (m, 1H), 5.30-5.24 (m, 2H), 5.15 (d, J=10.4 Hz, 1H), 4.53(t, J=8.4 Hz, 1H), 4.30-4.21 (m, 2H), 4.04 (dd, J=12.0, 4.0 Hz, 1H),3.94 (s, 3H), 3.38-3.29 (m, 1H), 2.60-2.50 (m, 2H), 2.13 (q, J=8.4 Hz,1H), 1.93 (dd, J=8.0, 6.0 Hz, 1H), 1.73-1.53 (m, 2H), 1.50 (s, 3H),1.44-1.23 (m, 16H), 1.02 (s, 9H), 0.90-0.80 (m, 2H) ppm; ¹³C NMR (100MHz, CDCl₃) δ 173.45, 172.52, 167.27, 160.22, 155.58, 154.23, 151.78,140.54, 134.40, 132.63, 129.36, 118.73, 118.59, 105.83, 79.78, 73.98,59.60, 58.75, 55.68, 54.28, 42.32, 36.52, 35.59, 34.96, 34.20, 30.65,28.21, 26.45, 21.47, 20.49, 20.45, 18.39, 13.97, 13.56 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₃₈H₅₅N₆O₉S, 771.3746; found 771.3735. Anal.RP-HPLC: t_(R) 10.33 min, purity 98%.

tert-Butyl((S)-1-((2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(10d)

The same procedure was used as described above for compound 3. Acid 6d(0.92 g, 1.71 mmol) was coupled with amine salt 8 (0.53 g, 1.88 mmol)using DIEA (1.15 mL, 6.96 mmol) and HATU (0.95 g, 2.50 mmol) to providecompound 10d (1.0 g, 77%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ9.83 (s, 1H), 7.80 (d, J=8.8 Hz, 1H), 7.26-7.22 (m, 2H), 7.18 (d, J=2.4Hz, 1H), 5.84 (br s, 1H), 5.72-5.63 (m, 1H), 5.27 (d, J=16.4 Hz, 1H),5.23 (d, J=9.2 Hz, 1H), 5.15 (d, J=10.4 Hz, 1H), 4.62 (t, J=8.0 Hz, 1H),4.38 (d, J=12.0 Hz, 1H), 4.21 (d, J=9.6 Hz, 1H), 4.03 (dd, J=11.6, 4.4Hz, 1H), 3.96 (s, 3H), 2.64-2.54 (m, 2H), 2.13 (q, J=8.8 Hz, 1H), 1.94(dd, J=8.0, 6.0 Hz, 1H), 1.75-1.58 (m, 2H), 1.50 (s, 3H), 1.44-1.38 (m,1H), 1.31 (s, 9H), 1.02 (s, 9H), 0.88-0.80 (m, 2H) ppm; ¹³C NMR (100MHz, CDCl₃) δ 173.35, 172.64, 167.17, 161.29, 155.66, 152.08, 140.87,135.95, 134.08, 132.60, 128.85, 120.08, 118.75, 105.89, 79.91, 75.56,59.53, 58.73, 55.82, 53.80, 42.38, 36.50, 35.43, 34.87, 34.00, 28.21,26.44, 21.32, 18.40, 13.99, 13.52 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₅H₄₈ClN₆O₉S, 763.2887; found 763.2878. Anal. RP-HPLC: t_(R) 9.82 min,purity 99%.

tert-Butyl((S)-1-((2S,4R)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(10e)

The same procedure was used as described above for compound 3. Acid 6e(0.78 g, 1.37 mmol) was coupled with amine salt 8 (0.48 g, 1.71 mmol)using DIEA (0.95 mL, 5.75 mmol) and HATU (0.85 g, 2.24 mmol) to providecompound 10e (0.82 g, 75%) as an off-white solid. ¹H NMR (400 MHz,CDCl₃) δ 9.80 (s, 1H), 7.81 (d, J=8.8 Hz, 1H), 7.48 (dd, J=8.8, 2.8 Hz,1H), 7.43 (d, J=2.8 Hz, 1H), 7.27-7.25 (m, 1H), 5.92 (br s, 1H),5.73-5.64 (m, 1H), 5.28 (d, J=17.2 Hz, 1H), 5.20 (d, J=9.6 Hz, 1H), 5.15(d, J=10.8 Hz, 1H), 4.56 (t, J=8.4 Hz, 1H), 4.34 (d, J=12.0 Hz, 1H),4.18 (d, J=9.6 Hz, 1H), 4.0 (dd, J=11.6, 3.6 Hz, 1H), 3.94 (s, 3H),2.64-2.51 (m, 2H), 2.13 (q, J=8.4 Hz, 1H), 1.95 (dd, J=8.0, 6.0 Hz, 1H),1.73-1.60 (m, 2H), 1.59 (s, 3H), 1.43-1.38 (m, 1H), 1.28 (s, 9H), 1.00(s, 9H), 0.89-0.81 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.53,172.82, 167.41, 159.76, 155.80, 151.85, 138.61, 137.20, 134.48 (q,J=35.9 Hz), 132.86, 128.21, 125.90, 120.81 (d, J=274.0 Hz), 118.96,107.68, 80.0, 75.16, 59.69, 58.90, 56.13, 54.12, 42.60, 36.75, 35.69,35.17, 34.28, 28.34, 26.65, 21.66, 18.65, 13.79, 13.44 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₃₆H₄₈F₃N₆O₉S, 797.3150; found 797.3146. Anal.RP-HPLC: t_(R) 10.10 min, purity 98%.

Cyclopentyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(11a)

Compound 3 (0.40 g, 0.54 mmol) was treated with a solution of 4 N HCl in1,4-dioxane (10 mL). After stirring the reaction mixture at roomtemperature for 3 h, solvents were evaporated under reduced pressure.The residue was triturated with diethyl ether (3×10 mL) and dried toyield the amine salt product (0.37 g, 100%) as a white powder.

A solution of the above amine salt (0.37 g, 0.54 mmol) in anhydrousCH₃CN (15 mL) was treated with DIEA (0.37 mL, 2.24 mmol) andN-(cyclopentyloxycarbonyloxy)-succinimide (0.15 g, 0.66 mmol). Thereaction mixture was stirred at room temperature for 36 h, thenconcentrated under reduced pressure and dried under high vacuum. Theresidue was purified by flash chromatography using 50-90% EtOAc/hexanesas the eluent to provide the target compound 11a (0.36 g, 88%) as awhite solid. ¹H NMR (500 MHz, CDCl₃) δ 10.03 (s, 1H), 7.83 (d, J=9.0 Hz,1H), 7.19 (dd, J=9.0, 2.8 Hz, 1H), 7.14 (d, J=2.5 Hz, 2H), 5.90 (br s,1H), 5.80-5.73 (m, 1H), 5.32 (d, J=9.5 Hz, 1H), 5.26 (d, J=17.0 Hz, 1H),5.15 (d, J=10.6 Hz, 1H), 4.90-4.86 (m, 1H), 4.51 (t, J=8.6 Hz, 1H),4.32-4.26 (m, 2H), 4.05 (dd, J=11.6, 3.6 Hz, 1H), 3.94 (s, 3H),2.93-2.84 (m, 3H), 2.57-2.53 (m, 2H), 2.12 (q, J=8.4 Hz, 1H), 1.96 (dd,J=8.0, 6.0 Hz, 1H), 1.76-1.45 (m, 9H), 1.36-1.33 (m, 1H), 1.28 (t, J=7.5Hz, 3H), 1.08-0.98 (m, 12H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 172.93,172.61, 168.54, 160.41, 156.49, 154.92, 148.91, 140.92, 134.60, 132.66,129.31, 118.81, 106.13, 78.06, 74.17, 60.02, 59.22, 55.82, 54.40, 41.96,35.68, 35.61, 34.38, 32.92, 32.71, 32.53, 31.41, 26.61, 23.80, 22.53,11.72, 6.40, 6.17 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₇H₅₁N₆O₉S,755.3433; found 755.3429. Anal. RP-HPLC: t_(R) 9.59 min, purity 95%.

Cyclopentyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(11b)

The same procedure was used as described above for compound 11a.Compound 9b (0.31 g, 0.42 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.30 mL, 1.82 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.12g, 0.53 mmol) to provide the target compound 11b (0.26 g, 84%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.05 (s, 1H), 7.80 (d, J=8.8 Hz,1H), 7.19 (dd, J=9.2, 2.8 Hz, 1H), 7.14 (d, J=2.8 Hz, 1H), 7.08 (s, 1H),5.88 (br s, 1H), 5.81-5.72 (m, 1H), 5.34 (d, J=9.6 Hz, 1H), 5.26 (d,J=17.2 Hz, 1H), 5.15 (d, J=10.0 Hz, 1H), 4.92-4.87 (m, 1H), 4.52 (t,J=8.0 Hz, 1H), 4.32-4.25 (m, 2H), 4.05 (dd, J=11.2, 4.0 Hz, 1H), 3.94(s, 3H), 2.94-2.87 (m, 1H), 2.57-2.51 (m, 5H), 2.11 (q, J=8.4 Hz, 1H),1.97 (dd, J=7.6, 5.6 Hz, 1H), 1.78-1.45 (m, 9H), 1.36-1.32 (m, 1H),1.08-0.98 (s, 12H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.73, 172.46,168.40, 160.26, 156.40, 155.16, 144.55, 140.89, 134.35, 132.48, 128.95,118.80, 118.69, 106.0, 77.94, 74.16, 59.87, 59.05, 55.69, 54.20, 41.79,35.57, 35.50, 34.17, 32.78, 32.60, 31.24, 26.47, 23.68, 22.41, 19.84,6.28, 6.22 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₆H₄₉N₆O₉S, 741.3276;found 741.3275. Anal. RP-HPLC: t_(R) 9.17 min, purity 99%.

Cyclopentyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(11c)

The same procedure was used as described above for compound 11a.Compound 9c (0.50 g, 0.66 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.44 mL, 2.66 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.16g, 0.70 mmol) to provide the target compound 11c (0.48 g, 95%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.07 (s, 1H), 7.83 (d, J=9.2 Hz,1H), 7.19-7.12 (m, 3H), 5.91 (br s, 1H), 5.80-5.72 (m, 1H), 5.38 (d,J=9.6 Hz, 1H), 5.26 (d, J=17.2 Hz, 1H), 5.13 (d, J=10.4 Hz, 1H),4.90-4.86 (m, 1H), 4.48 (t, J=8.8 Hz, 1H), 4.32-4.27 (m, 2H), 4.06 (dd,J=12.0, 4.0 Hz, 1H), 3.94 (s, 3H), 3.38-3.32 (m, 1H), 2.93-2.87 (m, 1H),2.55-2.51 (m, 2H), 2.12 (q, J=8.8 Hz, 1H), 1.96 (dd, J=8.4, 6.0 Hz, 1H),1.78-1.47 (m, 9H), 1.38-1.23 (m, 7H), 1.07-0.97 (m, 12H) ppm; ¹³C NMR(100 MHz, CDCl₃) δ 172.81, 172.34, 168.52, 160.22, 156.33, 154.23,151.80, 140.53, 134.43, 132.54, 129.36, 118.59, 105.82, 77.86, 73.99,59.92, 59.02, 55.67, 54.31, 41.77, 35.64, 35.51, 34.33, 32.78, 32.56,31.24, 30.65, 26.48, 26.18, 23.66, 22.50, 20.50, 20.46, 6.29, 6.20 ppm;HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₈H₅₃N₆O₉S, 769.3589; found 769.3587.Anal. RP-HPLC: t_(R) 10.15 min, purity 96%.

Cyclopentyl((S)-1-((2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(11d)

The same procedure was used as described above for compound 11a.Compound 9d (0.50 g, 0.67 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.45 mL, 2.72 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.16g, 0.70 mmol) to provide the target compound 11d (0.46 g, 90%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 10.03 (s, 1H), 7.81 (d, J=9.0 Hz,1H), 7.23 (dd, J=9.0, 3.0 Hz, 1H), 7.18 (d, J=3.0 Hz, 1H), 7.14 (br s,1H), 5.86 (br s, 1H), 5.78-5.72 (m, 1H), 5.33 (d, J=8.4 Hz, 1H), 5.27(d, J=17.0 Hz, 1H), 5.15 (d, J=10.6 Hz, 1H), 4.88-4.85 (m, 1H), 4.58 (t,J=8.4 Hz, 1H), 4.38 (d, J=12.0 Hz, 1H), 4.23 (d, J=10.0 Hz, 1H), 4.04(dd, J=11.6, 3.6 Hz, 1H), 3.96 (s, 3H), 2.92-2.88 (m, 1H), 2.57 (dd,J=8.0, 2.4 Hz, 2H), 2.12 (q, J=8.6 Hz, 1H), 1.97 (dd, J=7.6, 6.0 Hz,1H), 1.76-1.43 (m, 9H), 1.36-1.32 (m, 1H), 1.08-0.96 (m, 12H) ppm; ¹³CNMR (100 MHz, CDCl₃) δ 172.86, 172.61, 168.53, 161.47, 156.58, 152.27,141.03, 136.25, 134.30, 132.63, 129.01, 120.21, 118.81, 106.07, 78.16,75.68, 59.99, 59.17, 55.95, 53.93, 42.04, 35.64, 35.50, 34.26, 32.92,32.72, 31.40, 26.60, 23.82, 22.40, 6.40, 6.35 ppm; HRMS (ESI) m/z:[M+H]⁺ calcd for C₃₅H₄₆ClN₆O₉S, 761.2730; found 761.2730. Anal. RP-HPLC:t_(R) 9.63 min, purity 98%.

Cyclopentyl((S)-1-((2S,4R)-2-(((1R,2S)-1-((cyclopropylsulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(11e)

The same procedure was used as described above for compound 11a.Compound 9e (0.40 g, 0.51 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.35 mL, 2.10 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.13g, 0.57 mmol) to provide the target compound 11e (0.35 g, 86%) as anoff-white solid. ¹H NMR (400 MHz, CDCl₃) δ 10.05 (s, 1H), 7.81 (d, J=9.2Hz, 1H), 7.48 (dd, J=9.2, 2.8 Hz, 1H), 7.43 (d, J=2.8 Hz, 1H), 7.18 (s,1H), 5.93 (br s, 1H), 5.81-5.72 (m, 1H), 5.32-5.25 (m, 2H), 5.15 (d,J=11.2 Hz, 1H), 4.81-4.77 (m, 1H), 4.53 (t, J=8.4 Hz, 1H), 4.35 (d,J=12.0 Hz, 1H), 4.19 (d, J=9.6 Hz, 1H), 4.02 (dd, J=12.0, 4.0 Hz, 1H),3.94 (s, 3H), 2.94-2.88 (m, 1H), 2.56-2.52 (m, 2H), 2.13 (q, J=8.4 Hz,1H), 1.97 (dd, J=7.6, 5.6 Hz, 1H), 1.74-1.42 (m, 9H), 1.37-1.33 (m, 1H),1.25-1.0 (m, 12H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 172.69, 172.39,168.42, 159.54, 156.34, 151.65, 138.40, 136.96, 134.34 (q, J=35.8 Hz),132.50, 127.96, 125.67, 120.60 (d, J=273.6 Hz), 118.66, 107.42, 77.82,74.94, 59.77, 58.92, 55.90, 53.87, 41.82, 35.47, 35.43, 34.16, 32.75,32.42, 31.24, 26.41, 23.67, 23.62, 22.37, 6.26, 6.20 ppm; HRMS (ESI)m/z: [M+H]⁺ calcd for C₃₆H₄₆F₃N₆O₉S, 795.2994; found 795.2996. Anal.RP-HPLC: t_(R) 9.93 min, purity 97%.

Cyclopentyl((S)-1-((2S,4R)-4-((3-ethyl-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(12a)

The same procedure was used as described above for compound 11a.Compound 10a (0.35 g, 0.46 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.31 mL, 1.94 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.13g, 0.57 mmol) to provide the target compound 12a (0.34 g, 96%) as awhite solid. ¹H NMR (500 MHz, CDCl₃) δ 9.77 (s, 1H), 7.83 (d, J=9.0 Hz,1H), 7.25 (s, 1H, overlapping), 7.19 (dd, J=9.0, 2.5 Hz, 1H), 7.15 (d,J=2.5 Hz, 1H), 5.89 (br s, 1H), 5.72-5.64 (m, 1H), 5.33-5.25 (m, 2H),5.15 (d, J=10.5 Hz, 1H), 4.87 (m, 1H), 4.58 (t, J=8.0 Hz, 1H), 4.33 (d,J=12.0 Hz, 1H), 4.27 (d, J=10.0 Hz, 1H), 4.02 (dd, J=12.0, 4.0 Hz, 1H),3.95 (s, 3H), 2.86 (q, J=7.5 Hz, 2H), 2.67-2.62 (m, 1H), 2.56-2.51 (m,1H), 2.11 (q, J=8.5 Hz, 1H), 1.93 (dd, J=8.0, 6.5 Hz, 1H), 1.77-1.05 (m,13H), 1.38 (dd, J=9.0, 6.0 Hz, 1H), 1.27 (t, J=7.5 Hz, 3H), 1.03 (s,9H), 0.90-0.80 (m, 2H) ppm; ¹³C NMR (125 MHz, CDCl₃) δ 173.55, 172.78,167.25, 160.40, 156.48, 154.95, 148.92, 140.95, 134.60, 132.73, 129.30,118.90, 118.79, 106.15, 78.07, 74.10, 59.64, 59.25, 55.82, 54.31, 42.55,36.68, 35.54, 35.01, 34.10, 32.93, 32.71, 26.59, 23.80, 21.38, 18.54,14.15, 13.67, 11.70 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₈H₅₃N₆O₉S,769.3589; found 769.3584. Anal. RP-HPLC: t_(R) 9.79 min, purity 98%.

Cyclopentyl((S)-1-((2S,4R)-4-((7-methoxy-3-methylquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(12b)

The same procedure was used as described above for compound 11a.Compound 10b (0.40 g, 0.54 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.36 mL, 2.18 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.14g, 0.62 mmol) to provide the target compound 12b (0.34 g, 96%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 9.77 (s, 1H), 7.80 (d, J=9.0 Hz,1H), 7.32 (s, 1H), 7.19-7.14 (m, 2H), 5.87 (br s, 1H), 5.71-5.64 (m,1H), 5.38 (d, J=9.6 Hz, 1H), 5.27 (d, J=17.0 Hz, 1H), 5.15 (d, J=10.6Hz, 1H), 4.94-4.87 (m, 1H), 4.61 (t, J=8.0 Hz, 1H), 4.32 (d, J=11.6 Hz,1H), 4.27 (d, J=9.6 Hz, 1H), 4.03 (dd, J=11.6, 4.0 Hz, 1H), 3.94 (s,3H), 2.66-2.60 (m, 1H), 2.56-2.50 (m, 4H), 2.11 (q, J=8.4 Hz, 1H), 1.92(dd, J=8.0, 6.0 Hz, 1H), 1.80-1.49 (m, 13H), 1.37 (dd, J=9.0, 6.0 Hz,1H), 1.02 (s, 9H), 0.88-0.79 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ173.57, 172.73, 167.33, 160.40, 156.55, 155.34, 144.74, 141.06, 134.50,132.74, 129.08, 118.86, 106.20, 78.07, 74.25, 59.61, 59.26, 55.81,54.28, 42.50, 36.68, 35.50, 34.97, 34.11, 32.92, 32.75, 26.60, 23.81,21.41, 19.96, 18.52, 14.05, 13.71 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₇H₅₁N₆O₉S, 755.3433; found 755.3433. Anal. RP-HPLC: t_(R) 9.38 min,purity 98%.

Cyclopentyl((S)-1-((2S,4R)-4-((3-isopropyl-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(12c)

The same procedure was used as described above for compound 11a.Compound 10c (0.62 g, 0.80 mmol) was treated with 4 N HCl in 1,4-dioxane(12 mL) to yield the amine salt product, which was treated with DIEA(0.53 mL, 3.20 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.20g, 0.88 mmol) to provide the target compound 12c (0.58 g, 93%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 9.83 (s, 1H), 7.84 (d, J=9.2 Hz,1H), 7.23 (s, 1H), 7.20-7.13 (m, 2H), 5.89 (br s, 1H), 5.73-5.64 (m,1H), 5.35 (d, J=9.2 Hz, 1H), 5.27 (d, J=16.4 Hz, 1H), 5.14 (d, J=10.4Hz, 1H), 4.90-4.84 (m, 1H), 4.56 (t, J=8.0 Hz, 1H), 4.33-4.24 (m, 2H),4.04 (dd, J=12.0, 4.4 Hz, 1H), 3.94 (s, 3H), 3.38-3.31 (m, 1H),2.67-2.52 (m, 2H), 2.12 (q, J=8.0 Hz, 1H), 1.93 (dd, J=8.0, 6.0 Hz, 1H),1.77-1.50 (m, 13H), 1.41-1.25 (m, 7H), 1.02 (s, 9H), 0.89-0.80 (m, 2H)ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.37, 172.52, 167.22, 160.22, 156.29,154.26, 151.81, 140.55, 134.42, 132.59, 129.35, 118.76, 118.57, 105.84,77.86, 73.89, 59.55, 59.06, 55.67, 54.22, 42.32, 36.51, 35.51, 34.96,34.10, 32.80, 32.56, 30.65, 26.44, 23.66, 21.43, 20.50, 20.42, 18.40,13.95, 13.57 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₉H₅₅N₆O₉S,783.3746; found 783.3745. Anal. RP-HPLC: t_(R) 10.37 min, purity 98%.

Cyclopentyl((S)-1-((2S,4R)-4-((3-chloro-7-methoxyquinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(12d)

The same procedure was used as described above for compound 11a.Compound 10d (0.50 g, 0.65 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.43 mL, 2.60 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.16g, 0.70 mmol) to provide the target compound 12d (0.45 g, 89%) as awhite solid. ¹H NMR (400 MHz, CDCl₃) δ 9.79 (s, 1H), 7.80 (d, J=8.8 Hz,1H), 7.30 (s, 1H), 7.26-7.21 (m, 1H), 7.18 (d, J=2.0 Hz, 1H), 5.85 (brs, 1H), 5.73-5.64 (m, 1H), 5.35 (d, J=9.2 Hz, 1H), 5.27 (d, J=16.8 Hz,1H), 5.15 (d, J=10.8 Hz, 1H), 4.87-4.84 (m, 1H), 4.64 (t, J=7.6 Hz, 1H),4.40 (d, J=11.6 Hz, 1H), 4.23 (d, J=10.0 Hz, 1H), 4.02 (dd, J=11.6, 4.0Hz, 1H), 3.96 (s, 3H), 2.64-2.54 (m, 2H), 2.12 (q, J=8.4 Hz, 1H), 1.94(dd, J=7.6, 6.0 Hz, 1H), 1.78-1.49 (m, 13H), 1.39 (dd, J=9.2, 5.6 Hz,1H), 1.01 (s, 9H), 0.88-0.80 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ173.30, 172.60, 167.17, 161.27, 156.42, 152.14, 140.88, 136.12, 134.10,132.57, 128.82, 120.05, 118.80, 105.89, 78.01, 75.48, 59.53, 59.02,55.82, 53.74, 42.36, 36.50, 35.34, 34.86, 33.90, 32.78, 32.58, 26.43,23.70, 21.32, 18.40, 13.95, 13.56 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd forC₃₆H₄₈ClN₆O₉S, 775.2887; found 775.2890. Anal. RP-HPLC: t_(R) 9.87 min,purity 98%.

Cyclopentyl((S)-1-((2S,4R)-4-((7-methoxy-3-(trifluoromethyl)quinoxalin-2-yl)oxy)-2-(((1R,2S)-1-(((1-methylcyclopropyl)sulfonyl)carbamoyl)-2-vinylcyclopropyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)carbamate(12e)

The same procedure was used as described above for compound 11a.Compound 10e (0.40 g, 0.50 mmol) was treated with 4 N HCl in 1,4-dioxane(10 mL) to yield the amine salt product, which was treated with DIEA(0.35 mL, 2.10 mmol) and N-(cyclopentyloxycarbonyloxy)-succinimide (0.13g, 0.57 mmol) to provide the target compound 12e (0.38 g, 94%) as anoff-white solid. ¹H NMR (400 MHz, CDCl₃) δ 9.79 (s, 1H), 7.81 (d, J=9.2Hz, 1H), 7.48 (dd, J=8.8, 2.8 Hz, 1H), 7.43 (d, J=2.8 Hz, 1H), 7.32 (s,1H), 5.91 (br s, 1H), 5.73-5.63 (m, 1H), 5.30-5.25 (m, 2H), 5.16 (d,J=10.8 Hz, 1H), 4.80-4.75 (m, 1H), 4.60 (t, J=7.6 Hz, 1H), 4.37 (d,J=12.0 Hz, 1H), 4.19 (d, J=9.6 Hz, 1H), 3.98 (dd, J=11.6, 3.6 Hz, 1H),3.94 (s, 3H), 2.67-2.51 (m, 2H), 2.12 (q, J=8.0 Hz, 1H), 1.94 (dd,J=8.0, 6.0 Hz, 1H), 1.73-1.48 (m, 13H), 1.38 (dd, J=9.2, 5.6 Hz, 1H),0.99 (s, 9H), 0.89-0.81 (m, 2H) ppm; ¹³C NMR (100 MHz, CDCl₃) δ 173.26,172.60, 167.14, 159.51, 156.31, 151.68, 138.39, 136.96, 134.38 (q,J=36.0 Hz), 132.58, 127.98, 125.62, 120.60 (d, J=274.4 Hz), 118.76,107.42, 77.82, 74.86, 59.41, 58.95, 55.89, 53.79, 42.36, 36.50, 35.30,34.91, 33.89, 32.76, 32.40, 26.38, 23.66, 23.62, 21.34, 18.40, 13.95,13.56 ppm; HRMS (ESI) m/z: [M+H]⁺ calcd for C₃₇H₄₈F₃N₆O₉S, 809.3150;found 809.3157. Anal. RP-HPLC: t_(R) 10.16 min, purity 96%.

Expression and Purification of NS3/4A Protease Constructs

The HCV GT1a NS3/4A protease gene described in the Bristol Myers Squibbpatent⁵ was synthesized by GenScript and cloned into a PET28a expressionvector. The D168A and R155K genes were engineered using thesite-directed mutagenesis protocol from Stratagene. Protein expressionand purification were carried out as previously described. Briefly,transformed Escherichia coli BL21(DE3) cells were grown in LB mediacontaining 30 μg/mL of kanamycin antibiotic at 37° C. After reaching anOD₆₀₀ of 0.8, cultures were induced with 1 mM IPTG and harvested after 4h of expression. Cells were pelleted by centrifugation, resuspended inResuspension buffer [50 mM phosphate buffer, 500 mM NaCl, 10% glycerol,2 mM P-ME, pH 7.5] and frozen at −80° C. for storage.

Cell pellets were thawed and lysed via cell disruptor (MicrofluidicsInc.) two times to ensure sufficient DNA shearing. Lysate wascentrifuged at 19,000 rpm, for 25 min at 4° C. The soluble fraction wasapplied to a nickel column (Qiagen) pre-equilibrated with Resuspensionbuffer. The beads and soluble fraction were incubated at 4° C. for 1.5 hand the lysate was allowed to flow through. Beads were washed withResuspension buffer supplemented with 20 mM imidazole and eluted withResuspension buffer supplemented with 200 mM imidazole. The eluent wasdialyzed overnight (MWCO 10 kD) to remove the imidazole, and the His-tagwas simultaneously removed with thrombin treatment. The eluate wasjudged >90% pure by polyacrylamide gel electrophoresis, concentrated,flash and stored at −80° C.

Enzyme Inhibition Assays

For each assay, 2 nM of NS3/4A protease (GT1a, R155K and D168A) waspre-incubated at room temperature for 1 h with increasing concentrationof inhibitors in assay buffer (50 mM Tris, 5% glycerol, 10 mM DTT, 0.6mM LDAO, and 4% dimethyl sulfoxide, pH 7.5). Inhibition assays wereperformed in non-binding surface 96-well black half-area plates(Corning) in a reaction volume of 60 μL. The proteolytic reaction wasinitiated by the injection of 5 μL of HCV NS3/4A protease substrate(AnaSpec), to a final concentration of 200 nM and kinetically monitoredusing a Perkin Elmer EnVision plate reader (excitation at 485 nm,emission at 530 nm). Three independent data sets were collected for eachinhibitor with each protease construct. Each inhibitor titrationincluded at least 12 inhibitor concentration points, which were globallyfit to the Morrison equation to obtain the K, value. Gibbs free energyof binding was calculated using the following equation: ΔG=RTlnK_(i)

Cell-Based Drug Susceptibility Assays

Mutations (R155K, D168A and A156T) were constructed by site-directedmutagenesis using a Con1 (genotype 1b) luciferase reporter repliconcontaining the H77 (genotype 1a) NS3 sequence.⁶ Replicon RNA of eachprotease variant was introduced into Huh7 cells by electroporation.Replication was then assessed in the presence of increasingconcentrations of protease inhibitors by measuring luciferase activity(relative light units) 96 h after electroporation. The drugconcentrations required to inhibit replicon replication by 50% (EC₅₀)were calculated directly from the drug inhibition curves.

Crystallization and Structure Determination

Protein expression and purification were carried out as previouslydescribed (see Supporting Information for details). The Ni-NTA purifiedWT1a protein was thawed, concentrated to 3 mg/mL, and loaded on a HiLoadSuperdex75 16/60 column equilibrated with gel filtration buffer (25 mMMES, 500 mM NaCl, 10% glycerol, and 2 mM DTT, pH 6.5). The proteasefractions were pooled and concentrated to 25 mg/mL with an AmiconUltra-15 10 kDa filter unit (Millipore). The concentrated samples wereincubated for 1 h with 3:1 molar excess of inhibitor.Diffraction-quality crystals were obtained overnight by mixing equalvolumes of concentrated protein solution with precipitant solution(20-26% PEG-3350, 0.1 M sodium MES buffer, 4% ammonium sulfate, pH 6.5)at RT in 24-well VDX hanging drop trays. Crystals were harvested anddata was collected at 100 K. Cryogenic conditions contained theprecipitant solution supplemented with 15% glycerol or ethylene glycol.

X-ray diffraction data were collected in-house using the Rigaku X-raysystem with a Saturn 944 detector. All datasets were processed usingHKL-3000. Structures were solved by molecular replacement using PHASER.Model building and refinement were performed using Coot and PHENIX,respectively. The final structures were evaluated with MolProbity priorto deposition in the PDB. To limit the possibility of model biasthroughout the refinement process, 5% of the data were reserved for thefree R-value calculation. Structure analysis, superposition and figuregeneration were done using PyMOL. X-ray data collection andcrystallographic refinement statistics are presented in Table 10.

Applicant's disclosure is described herein in preferred embodiments withreference to the Figures, in which like numbers represent the same orsimilar elements. Reference throughout this specification to “oneembodiment,” “an embodiment,” or similar language means that aparticular feature, structure, or characteristic described in connectionwith the embodiment is included in at least one embodiment of thepresent invention. Thus, appearances of the phrases “in one embodiment,”“in an embodiment,” and similar language throughout this specificationmay, but do not necessarily, all refer to the same embodiment.

The described features, structures, or characteristics of Applicant'sdisclosure may be combined in any suitable manner in one or moreembodiments. In the description, herein, numerous specific details arerecited to provide a thorough understanding of embodiments of theinvention. One skilled in the relevant art will recognize, however, thatApplicant's composition and/or method may be practiced without one ormore of the specific details, or with other methods, components,materials, and so forth. In other instances, well-known structures,materials, or operations are not shown or described in detail to avoidobscuring aspects of the disclosure.

In this specification and the appended claims, the singular forms “a,”“an,” and “the” include plural reference, unless the context clearlydictates otherwise.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art. Although any methods and materials similar or equivalent tothose described herein can also be used in the practice or testing ofthe present disclosure, the preferred methods and materials are nowdescribed. Methods recited herein may be carried out in any order thatis logically possible, in addition to a particular order disclosed.

INCORPORATION BY REFERENCE

References and citations to other documents, such as patents, patentapplications, patent publications, journals, books, papers, webcontents, have been made in this disclosure. All such documents arehereby incorporated herein by reference in their entirety for allpurposes. Any material, or portion thereof, that is said to beincorporated by reference herein, but which conflicts with existingdefinitions, statements, or other disclosure material explicitly setforth herein is only incorporated to the extent that no conflict arisesbetween that incorporated material and the present disclosure material.In the event of a conflict, the conflict is to be resolved in favor ofthe present disclosure as the preferred disclosure.

EQUIVALENTS

The representative examples are intended to help illustrate theinvention, and are not intended to, nor should they be construed to,limit the scope of the invention. Indeed, various modifications of theinvention and many further embodiments thereof, in addition to thoseshown and described herein, will become apparent to those skilled in theart from the full contents of this document, including the examples andthe references to the scientific and patent literature included herein.The examples contain important additional information, exemplificationand guidance that can be adapted to the practice of this invention inits various embodiments and equivalents thereof.

1-21. (canceled)
 22. A compound having the structural formula (II),

wherein each of X and Y is independently selected from O, NR and CRR′,provided that at least one of X and Y is NR; R¹ is selected from H, aC₁-C₆ alkoxy, aryloxy, C₁-C₆ alkyl, halogen, —(C═O)N—R, —N(C═O)R,—(SO₂)NR₂ group; R² is selected from H, halogen, a C₁-C₆ alkyl, aryl,—CN, CF₃, CHF₂, CH₂F; R³ is selected from H, a C₁-C₆ alkyl, CH₂F, CHF₂;R⁴ is selected from an alkyl, hetero-alkyl, aryl, hetero-aryl group,—NH—C(═O)—R; R⁵ is H, halogen, or an alkyl group; R⁶ is H, halogen, oran alkyl group; R⁷ is H, halogen, or an alkyl group; each R⁸ isindependently selected from H, halogen, or an alkyl group; each R⁹ isindependently selected from H, halogen, or an alkyl group; each R¹⁰ isindependently selected from H, halogen, or an alkyl group; each R¹¹ isindependently selected from H, halogen, or an alkyl group; and each Rand R′ is independently a H or an alkyl group, or a pharmaceuticallyacceptable form thereof.
 23. The compound of claim 22, having thestructural formula (IIa),


24. The compound of claim 23, wherein each of R⁵, R⁶, R⁷, R¹, R⁹, R¹⁰,R¹¹ is H, having the structural formula (IIb),


25. The compound of claim 24, wherein R¹ is at the 7-position, havingthe structural formula (III),


26. The compound of claim 25, wherein R³ is H.
 27. The compound of claim25, wherein R³ is a C₁-C₆ alkyl group.
 28. The compound of claim 27,wherein R³ is a C₁-C₂ alkyl group.
 29. The compound of claim 25, whereinR¹ is H.
 30. The compound of claim 25, wherein R¹ is a C₁-C₆ alkoxygroup.
 31. (canceled)
 32. The compound of claim 25, wherein R² is aC₁-C₆ alkyl group.
 33. The compound of claim 25, wherein R² is ahalogen.
 34. The compound of claim 25, wherein R² is an aryl group. 35.The compound of claim 34, wherein R² is 2-thiophene.
 36. The compound ofclaim 25, wherein R⁴ is a C₁-C₆ alkyl group.
 37. (canceled)
 38. Thecompound of claim 22, selected from:


39. The compound of claim 22, having the structural formula of (IV):

wherein R¹² is H, halogen, or an alkyl group; R¹³ is H, halogen, analkyl group, hetero-alkyl, aryl, or hetero-aryl group; and each R and R′is independently a H or an alkyl group. 40-55. (canceled)
 56. Thecompound of claim 39:


57. (canceled)
 58. A pharmaceutical composition comprising a compound ofclaim 22 effective to treat or reduce HCV infection or a related diseaseor disorder, in a mammal, including a human, and a pharmaceuticallyacceptable excipient, carrier, or diluent. 59.-66. (canceled)
 67. Amethod for treating or reducing HCV infection, or a related disease ordisorder, comprising administering to a subject in need thereof apharmaceutical composition comprising a compound of claim
 22. 68-75.(canceled)
 76. A method for inhibiting or inactivating HCV NS3/4Aprotease, comprising administering to a subject in need thereof apharmaceutical composition comprising a compound of claim
 22. 77-81.(canceled)